From eaa250367a9350ab316615f2b00ca5d9374e741e Mon Sep 17 00:00:00 2001
From: Tzu-ping Chung <uranusjr@gmail.com>
Date: Tue, 7 Jun 2022 17:52:38 +0800
Subject: [PATCH] Migrate tests to use pathlib.Path

The pip-specific Path implementation has been removed, and all its
usages replaced by pathlib.Path. The tmpdir and tmpdir_factory fixtures
are also removed, and all usages are replaced by tmp_path and
tmp_path_factory, which use pathlib.Path.

The pip() function now also accepts pathlib.Path so we don't need to put
str() everywhere. Path arguments are coerced with os.fspath() into str.
---
 tests/conftest.py                             | 145 +++++++------
 tests/functional/test_broken_stdout.py        |  10 +-
 tests/functional/test_build_env.py            |   7 +-
 tests/functional/test_completion.py           |  20 +-
 tests/functional/test_config_settings.py      |   4 +-
 tests/functional/test_download.py             | 127 ++++++------
 tests/functional/test_fast_deps.py            |   3 +-
 tests/functional/test_freeze.py               |  71 ++++---
 tests/functional/test_hash.py                 |  23 ++-
 tests/functional/test_install.py              | 168 ++++++++--------
 tests/functional/test_install_cleanup.py      |  12 +-
 tests/functional/test_install_config.py       |  26 +--
 tests/functional/test_install_direct_url.py   |  18 +-
 tests/functional/test_install_extras.py       |   8 +-
 tests/functional/test_install_index.py        |   9 +-
 tests/functional/test_install_reqs.py         |  84 ++++----
 tests/functional/test_install_upgrade.py      |  15 +-
 tests/functional/test_install_user.py         |  13 +-
 tests/functional/test_install_vcs_git.py      |  76 +++----
 tests/functional/test_install_wheel.py        | 157 ++++++++-------
 tests/functional/test_list.py                 |  56 +++---
 tests/functional/test_new_resolver.py         | 107 +++++-----
 tests/functional/test_new_resolver_errors.py  |  17 +-
 tests/functional/test_new_resolver_hashes.py  |  21 +-
 tests/functional/test_new_resolver_target.py  |  10 +-
 tests/functional/test_new_resolver_user.py    |   6 +-
 tests/functional/test_pep517.py               | 130 +++++++-----
 tests/functional/test_pep660.py               |  60 +++---
 tests/functional/test_show.py                 |   2 +-
 tests/functional/test_uninstall.py            |  42 ++--
 tests/functional/test_vcs_bazaar.py           |  13 +-
 tests/functional/test_vcs_git.py              |  56 +++---
 tests/functional/test_vcs_mercurial.py        |   4 +-
 tests/functional/test_vcs_subversion.py       |  14 +-
 tests/functional/test_warning.py              |  14 +-
 tests/functional/test_wheel.py                |  42 ++--
 tests/lib/__init__.py                         | 178 ++++++++--------
 tests/lib/direct_url.py                       |   7 +-
 tests/lib/git_submodule_helpers.py            |  18 +-
 tests/lib/local_repos.py                      |  26 ++-
 tests/lib/path.py                             | 190 ------------------
 tests/lib/server.py                           |  44 ++--
 tests/lib/test_wheel.py                       |   8 +-
 tests/lib/venv.py                             |  21 +-
 tests/lib/wheel.py                            |  10 +-
 .../resolution_resolvelib/test_requirement.py |  11 +-
 tests/unit/test_base_command.py               |  30 +--
 tests/unit/test_cache.py                      |  10 +-
 tests/unit/test_collector.py                  |  23 +--
 tests/unit/test_compat.py                     |  14 +-
 tests/unit/test_direct_url_helpers.py         |  11 +-
 tests/unit/test_locations.py                  |  10 +-
 tests/unit/test_network_cache.py              |  32 +--
 tests/unit/test_network_session.py            |  22 +-
 tests/unit/test_operations_prepare.py         |  61 +++---
 tests/unit/test_options.py                    |   3 +-
 tests/unit/test_pep517.py                     |  14 +-
 tests/unit/test_req.py                        |  41 ++--
 tests/unit/test_req_file.py                   | 122 ++++++-----
 tests/unit/test_req_install.py                |  15 +-
 tests/unit/test_req_uninstall.py              |  97 ++++-----
 tests/unit/test_resolution_legacy_resolver.py |   2 +-
 tests/unit/test_self_check_outdated.py        |  22 +-
 tests/unit/test_utils.py                      |  34 ++--
 tests/unit/test_utils_filesystem.py           |  14 +-
 tests/unit/test_utils_temp_dir.py             |  16 +-
 tests/unit/test_utils_unpacking.py            |  14 +-
 tests/unit/test_utils_virtualenv.py           |  14 +-
 tests/unit/test_utils_wheel.py                |  51 +++--
 tests/unit/test_vcs.py                        |   5 +-
 tests/unit/test_vcs_mercurial.py              |  17 +-
 tests/unit/test_wheel.py                      |  96 +++++----
 tests/unit/test_wheel_builder.py              |   4 +-
 tools/protected_pip.py                        |   7 +-
 74 files changed, 1423 insertions(+), 1481 deletions(-)
 delete mode 100644 tests/lib/path.py

diff --git a/tests/conftest.py b/tests/conftest.py
index c137f844129..6991084e6b5 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -2,16 +2,25 @@
 import fnmatch
 import io
 import os
+import pathlib
 import re
 import shutil
 import subprocess
 import sys
 import time
 from contextlib import ExitStack, contextmanager
-from typing import TYPE_CHECKING, Callable, Dict, Iterable, Iterator, List, Optional
+from typing import (
+    TYPE_CHECKING,
+    Callable,
+    Dict,
+    Iterable,
+    Iterator,
+    List,
+    Optional,
+    Union,
+)
 from unittest.mock import patch
 
-import py.path
 import pytest
 
 # Config will be available from the public API in pytest >= 7.0.0:
@@ -27,7 +36,6 @@
 from pip._internal.locations import _USE_SYSCONFIG
 from pip._internal.utils.temp_dir import global_tempdir_manager
 from tests.lib import DATA_DIR, SRC_DIR, PipTestEnvironment, TestData
-from tests.lib.path import Path
 from tests.lib.server import MockServer as _MockServer
 from tests.lib.server import make_mock_server, server_running
 from tests.lib.venv import VirtualEnvironment, VirtualEnvironmentType
@@ -37,7 +45,7 @@
 if TYPE_CHECKING:
     from typing import Protocol
 
-    from wsgi import WSGIApplication
+    from _typeshed.wsgi import WSGIApplication
 else:
     # TODO: Protocol was introduced in Python 3.8. Remove this branch when
     # dropping support for Python 3.7.
@@ -146,42 +154,44 @@ def resolver_variant(request: pytest.FixtureRequest) -> Iterator[str]:
 
 
 @pytest.fixture(scope="session")
-def tmpdir_factory(
-    request: pytest.FixtureRequest, tmpdir_factory: pytest.TempdirFactory
-) -> Iterator[pytest.TempdirFactory]:
+def tmp_path_factory(
+    request: pytest.FixtureRequest, tmp_path_factory: pytest.TempPathFactory
+) -> Iterator[pytest.TempPathFactory]:
     """Modified `tmpdir_factory` session fixture
     that will automatically cleanup after itself.
     """
-    yield tmpdir_factory
+    yield tmp_path_factory
     if not request.config.getoption("--keep-tmpdir"):
         shutil.rmtree(
-            tmpdir_factory.getbasetemp(),
+            tmp_path_factory.getbasetemp(),
             ignore_errors=True,
         )
 
 
 @pytest.fixture
-def tmpdir(request: pytest.FixtureRequest, tmpdir: py.path.local) -> Iterator[Path]:
+def tmp_path(
+    request: pytest.FixtureRequest,
+    tmp_path: pathlib.Path,
+) -> Iterator[pathlib.Path]:
     """
     Return a temporary directory path object which is unique to each test
     function invocation, created as a sub directory of the base temporary
-    directory. The returned object is a ``tests.lib.path.Path`` object.
+    directory. The returned object is a ``pathlib.Path`` object.
 
-    This uses the built-in tmpdir fixture from pytest itself but modified
-    to return our typical path object instead of py.path.local as well as
-    deleting the temporary directories at the end of each test case.
+    This uses the built-in tmp_path fixture from pytest itself, but deletes the
+    temporary directories at the end of each test case.
     """
-    assert tmpdir.isdir()
-    yield Path(str(tmpdir))
+    assert tmp_path.is_dir()
+    yield tmp_path
     # Clear out the temporary directory after the test has finished using it.
     # This should prevent us from needing a multiple gigabyte temporary
     # directory while running the tests.
     if not request.config.getoption("--keep-tmpdir"):
-        tmpdir.remove(ignore_errors=True)
+        shutil.rmtree(tmp_path, ignore_errors=True)
 
 
 @pytest.fixture(autouse=True)
-def isolate(tmpdir: Path, monkeypatch: pytest.MonkeyPatch) -> None:
+def isolate(tmp_path: pathlib.Path, monkeypatch: pytest.MonkeyPatch) -> None:
     """
     Isolate our tests so that things like global configuration files and the
     like do not affect our test results.
@@ -194,11 +204,11 @@ def isolate(tmpdir: Path, monkeypatch: pytest.MonkeyPatch) -> None:
     #       as well as user level configuration files.
 
     # Create a directory to use as our home location.
-    home_dir = os.path.join(str(tmpdir), "home")
+    home_dir = os.path.join(tmp_path, "home")
     os.makedirs(home_dir)
 
     # Create a directory to use as a fake root
-    fake_root = os.path.join(str(tmpdir), "fake-root")
+    fake_root = os.path.join(tmp_path, "fake-root")
     os.makedirs(fake_root)
 
     if sys.platform == "win32":
@@ -296,7 +306,7 @@ def scoped_global_tempdir_manager(request: pytest.FixtureRequest) -> Iterator[No
 
 
 @pytest.fixture(scope="session")
-def pip_src(tmpdir_factory: pytest.TempdirFactory) -> Path:
+def pip_src(tmp_path_factory: pytest.TempPathFactory) -> pathlib.Path:
     def not_code_files_and_folders(path: str, names: List[str]) -> Iterable[str]:
         # In the root directory...
         if path == SRC_DIR:
@@ -317,7 +327,7 @@ def not_code_files_and_folders(path: str, names: List[str]) -> Iterable[str]:
             ignored.update(fnmatch.filter(names, pattern))
         return ignored
 
-    pip_src = Path(str(tmpdir_factory.mktemp("pip_src"))).joinpath("pip_src")
+    pip_src = tmp_path_factory.mktemp("pip_src").joinpath("pip_src")
     # Copy over our source tree so that each use is self contained
     shutil.copytree(
         SRC_DIR,
@@ -328,11 +338,11 @@ def not_code_files_and_folders(path: str, names: List[str]) -> Iterable[str]:
 
 
 def _common_wheel_editable_install(
-    tmpdir_factory: pytest.TempdirFactory, common_wheels: Path, package: str
-) -> Path:
+    tmp_path_factory: pytest.TempPathFactory, common_wheels: pathlib.Path, package: str
+) -> pathlib.Path:
     wheel_candidates = list(common_wheels.glob(f"{package}-*.whl"))
     assert len(wheel_candidates) == 1, wheel_candidates
-    install_dir = Path(str(tmpdir_factory.mktemp(package))) / "install"
+    install_dir = tmp_path_factory.mktemp(package) / "install"
     Wheel(wheel_candidates[0]).install_as_egg(install_dir)
     (install_dir / "EGG-INFO").rename(install_dir / f"{package}.egg-info")
     assert compileall.compile_dir(str(install_dir), quiet=1)
@@ -341,25 +351,28 @@ def _common_wheel_editable_install(
 
 @pytest.fixture(scope="session")
 def setuptools_install(
-    tmpdir_factory: pytest.TempdirFactory, common_wheels: Path
-) -> Path:
-    return _common_wheel_editable_install(tmpdir_factory, common_wheels, "setuptools")
+    tmp_path_factory: pytest.TempPathFactory, common_wheels: pathlib.Path
+) -> pathlib.Path:
+    return _common_wheel_editable_install(tmp_path_factory, common_wheels, "setuptools")
 
 
 @pytest.fixture(scope="session")
-def wheel_install(tmpdir_factory: pytest.TempdirFactory, common_wheels: Path) -> Path:
-    return _common_wheel_editable_install(tmpdir_factory, common_wheels, "wheel")
+def wheel_install(
+    tmp_path_factory: pytest.TempPathFactory,
+    common_wheels: pathlib.Path,
+) -> pathlib.Path:
+    return _common_wheel_editable_install(tmp_path_factory, common_wheels, "wheel")
 
 
 @pytest.fixture(scope="session")
 def coverage_install(
-    tmpdir_factory: pytest.TempdirFactory, common_wheels: Path
-) -> Path:
-    return _common_wheel_editable_install(tmpdir_factory, common_wheels, "coverage")
+    tmp_path_factory: pytest.TempPathFactory, common_wheels: pathlib.Path
+) -> pathlib.Path:
+    return _common_wheel_editable_install(tmp_path_factory, common_wheels, "coverage")
 
 
 def install_egg_link(
-    venv: VirtualEnvironment, project_name: str, egg_info_dir: Path
+    venv: VirtualEnvironment, project_name: str, egg_info_dir: pathlib.Path
 ) -> None:
     with open(venv.site / "easy-install.pth", "a") as fp:
         fp.write(str(egg_info_dir.resolve()) + "\n")
@@ -370,10 +383,10 @@ def install_egg_link(
 @pytest.fixture(scope="session")
 def virtualenv_template(
     request: pytest.FixtureRequest,
-    tmpdir_factory: pytest.TempdirFactory,
-    pip_src: Path,
-    setuptools_install: Path,
-    coverage_install: Path,
+    tmp_path_factory: pytest.TempPathFactory,
+    pip_src: pathlib.Path,
+    setuptools_install: pathlib.Path,
+    coverage_install: pathlib.Path,
 ) -> Iterator[VirtualEnvironment]:
 
     venv_type: VirtualEnvironmentType
@@ -383,12 +396,12 @@ def virtualenv_template(
         venv_type = "virtualenv"
 
     # Create the virtual environment
-    tmpdir = Path(str(tmpdir_factory.mktemp("virtualenv")))
-    venv = VirtualEnvironment(tmpdir.joinpath("venv_orig"), venv_type=venv_type)
+    tmp_path = tmp_path_factory.mktemp("virtualenv")
+    venv = VirtualEnvironment(tmp_path.joinpath("venv_orig"), venv_type=venv_type)
 
     # Install setuptools and pip.
     install_egg_link(venv, "setuptools", setuptools_install)
-    pip_editable = Path(str(tmpdir_factory.mktemp("pip"))) / "pip"
+    pip_editable = tmp_path_factory.mktemp("pip") / "pip"
     shutil.copytree(pip_src, pip_editable, symlinks=True)
     # noxfile.py is Python 3 only
     assert compileall.compile_dir(
@@ -420,7 +433,7 @@ def virtualenv_template(
 
     # Rename original virtualenv directory to make sure
     # it's not reused by mistake from one of the copies.
-    venv_template = tmpdir / "venv_template"
+    venv_template = tmp_path / "venv_template"
     venv.move(venv_template)
     yield venv
 
@@ -428,16 +441,17 @@ def virtualenv_template(
 @pytest.fixture(scope="session")
 def virtualenv_factory(
     virtualenv_template: VirtualEnvironment,
-) -> Callable[[Path], VirtualEnvironment]:
-    def factory(tmpdir: Path) -> VirtualEnvironment:
-        return VirtualEnvironment(tmpdir, virtualenv_template)
+) -> Callable[[pathlib.Path], VirtualEnvironment]:
+    def factory(tmp_path: pathlib.Path) -> VirtualEnvironment:
+        return VirtualEnvironment(tmp_path, virtualenv_template)
 
     return factory
 
 
 @pytest.fixture
 def virtualenv(
-    virtualenv_factory: Callable[[Path], VirtualEnvironment], tmpdir: Path
+    virtualenv_factory: Callable[[pathlib.Path], VirtualEnvironment],
+    tmp_path: pathlib.Path,
 ) -> Iterator[VirtualEnvironment]:
     """
     Return a virtual environment which is unique to each test function
@@ -445,33 +459,34 @@ def virtualenv(
     temporary directory. The returned object is a
     ``tests.lib.venv.VirtualEnvironment`` object.
     """
-    yield virtualenv_factory(tmpdir.joinpath("workspace", "venv"))
+    yield virtualenv_factory(tmp_path.joinpath("workspace", "venv"))
 
 
 @pytest.fixture
-def with_wheel(virtualenv: VirtualEnvironment, wheel_install: Path) -> None:
+def with_wheel(virtualenv: VirtualEnvironment, wheel_install: pathlib.Path) -> None:
     install_egg_link(virtualenv, "wheel", wheel_install)
 
 
 class ScriptFactory(Protocol):
     def __call__(
-        self, tmpdir: Path, virtualenv: Optional[VirtualEnvironment] = None
+        self, tmp_path: pathlib.Path, virtualenv: Optional[VirtualEnvironment] = None
     ) -> PipTestEnvironment:
         ...
 
 
 @pytest.fixture(scope="session")
 def script_factory(
-    virtualenv_factory: Callable[[Path], VirtualEnvironment], deprecated_python: bool
+    virtualenv_factory: Callable[[pathlib.Path], VirtualEnvironment],
+    deprecated_python: bool,
 ) -> ScriptFactory:
     def factory(
-        tmpdir: Path, virtualenv: Optional[VirtualEnvironment] = None
+        tmp_path: pathlib.Path, virtualenv: Optional[VirtualEnvironment] = None
     ) -> PipTestEnvironment:
         if virtualenv is None:
-            virtualenv = virtualenv_factory(tmpdir.joinpath("venv"))
+            virtualenv = virtualenv_factory(tmp_path.joinpath("venv"))
         return PipTestEnvironment(
             # The base location for our test environment
-            tmpdir,
+            tmp_path,
             # Tell the Test Environment where our virtualenv is located
             virtualenv=virtualenv,
             # Do not ignore hidden files, they need to be checked as well
@@ -491,9 +506,9 @@ def factory(
 
 @pytest.fixture
 def script(
-    tmpdir: Path,
+    tmp_path: pathlib.Path,
     virtualenv: VirtualEnvironment,
-    script_factory: Callable[[Path, Optional[VirtualEnvironment]], PipTestEnvironment],
+    script_factory: ScriptFactory,
 ) -> PipTestEnvironment:
     """
     Return a PipTestEnvironment which is unique to each test function and
@@ -501,23 +516,23 @@ def script(
     test function. The returned object is a
     ``tests.lib.PipTestEnvironment``.
     """
-    return script_factory(tmpdir.joinpath("workspace"), virtualenv)
+    return script_factory(tmp_path.joinpath("workspace"), virtualenv)
 
 
 @pytest.fixture(scope="session")
-def common_wheels() -> Path:
+def common_wheels() -> pathlib.Path:
     """Provide a directory with latest setuptools and wheel wheels"""
     return DATA_DIR.joinpath("common_wheels")
 
 
 @pytest.fixture(scope="session")
-def shared_data(tmpdir_factory: pytest.TempdirFactory) -> TestData:
-    return TestData.copy(Path(str(tmpdir_factory.mktemp("data"))))
+def shared_data(tmp_path_factory: pytest.TempPathFactory) -> TestData:
+    return TestData.copy(tmp_path_factory.mktemp("data"))
 
 
 @pytest.fixture
-def data(tmpdir: Path) -> TestData:
-    return TestData.copy(tmpdir.joinpath("data"))
+def data(tmp_path: pathlib.Path) -> TestData:
+    return TestData.copy(tmp_path.joinpath("data"))
 
 
 class InMemoryPipResult:
@@ -527,12 +542,12 @@ def __init__(self, returncode: int, stdout: str) -> None:
 
 
 class InMemoryPip:
-    def pip(self, *args: str) -> InMemoryPipResult:
+    def pip(self, *args: Union[str, pathlib.Path]) -> InMemoryPipResult:
         orig_stdout = sys.stdout
         stdout = io.StringIO()
         sys.stdout = stdout
         try:
-            returncode = pip_entry_point(list(args))
+            returncode = pip_entry_point([os.fspath(a) for a in args])
         except SystemExit as e:
             returncode = e.code or 0
         finally:
@@ -555,7 +570,7 @@ def deprecated_python() -> bool:
 
 
 @pytest.fixture(scope="session")
-def cert_factory(tmpdir_factory: pytest.TempdirFactory) -> CertFactory:
+def cert_factory(tmp_path_factory: pytest.TempPathFactory) -> CertFactory:
     # Delay the import requiring cryptography in order to make it possible
     # to deselect relevant tests on systems where cryptography cannot
     # be installed.
@@ -563,7 +578,7 @@ def cert_factory(tmpdir_factory: pytest.TempdirFactory) -> CertFactory:
 
     def factory() -> str:
         """Returns path to cert/key file."""
-        output_path = Path(str(tmpdir_factory.mktemp("certs"))) / "cert.pem"
+        output_path = tmp_path_factory.mktemp("certs") / "cert.pem"
         # Must be Text on PY2.
         cert, key = make_tls_cert("localhost")
         with open(str(output_path), "wb") as f:
diff --git a/tests/functional/test_broken_stdout.py b/tests/functional/test_broken_stdout.py
index e7313244379..22bcc06f29c 100644
--- a/tests/functional/test_broken_stdout.py
+++ b/tests/functional/test_broken_stdout.py
@@ -1,9 +1,8 @@
 import os
+import pathlib
 import subprocess
 from typing import List, Tuple
 
-from tests.lib.path import Path
-
 _BROKEN_STDOUT_RETURN_CODE = 120
 
 
@@ -47,11 +46,14 @@ def test_broken_stdout_pipe(deprecated_python: bool) -> None:
     assert returncode == _BROKEN_STDOUT_RETURN_CODE
 
 
-def test_broken_stdout_pipe__log_option(deprecated_python: bool, tmpdir: Path) -> None:
+def test_broken_stdout_pipe__log_option(
+    deprecated_python: bool,
+    tmp_path: pathlib.Path,
+) -> None:
     """
     Test a broken pipe to stdout when --log is passed.
     """
-    log_path = os.path.join(str(tmpdir), "log.txt")
+    log_path = os.path.join(tmp_path, "log.txt")
     stderr, returncode = setup_broken_stdout_test(
         ["pip", "--log", log_path, "list"],
         deprecated_python=deprecated_python,
diff --git a/tests/functional/test_build_env.py b/tests/functional/test_build_env.py
index 1b9f42d94c0..d2ab79681ed 100644
--- a/tests/functional/test_build_env.py
+++ b/tests/functional/test_build_env.py
@@ -1,3 +1,4 @@
+import os
 from textwrap import dedent
 from typing import Optional
 
@@ -69,11 +70,11 @@ def run_with_build_env(
             "    ",
         )
     )
-    args = ["python", build_env_script]
+    args = ["python", os.fspath(build_env_script)]
     if test_script_contents is not None:
         test_script = script.scratch_path / "test.py"
         test_script.write_text(dedent(test_script_contents))
-        args.append(test_script)
+        args.append(os.fspath(test_script))
     return script.run(*args)
 
 
@@ -89,7 +90,7 @@ def test_build_env_allow_empty_requirements_install() -> None:
 def test_build_env_allow_only_one_install(script: PipTestEnvironment) -> None:
     create_basic_wheel_for_package(script, "foo", "1.0")
     create_basic_wheel_for_package(script, "bar", "1.0")
-    finder = make_test_finder(find_links=[script.scratch_path])
+    finder = make_test_finder(find_links=[os.fspath(script.scratch_path)])
     build_env = BuildEnvironment()
     for prefix in ("normal", "overlay"):
         build_env.install_requirements(
diff --git a/tests/functional/test_completion.py b/tests/functional/test_completion.py
index ba302a69b18..d849007a595 100644
--- a/tests/functional/test_completion.py
+++ b/tests/functional/test_completion.py
@@ -1,12 +1,12 @@
 import os
+import pathlib
 import sys
-from typing import TYPE_CHECKING, Optional, Tuple
+from typing import TYPE_CHECKING, Tuple, Union
 
 import pytest
 
 from tests.conftest import ScriptFactory
 from tests.lib import PipTestEnvironment, TestData, TestPipResult
-from tests.lib.path import Path
 
 if TYPE_CHECKING:
     from typing import Protocol
@@ -83,12 +83,12 @@
 
 @pytest.fixture(scope="session")
 def script_with_launchers(
-    tmpdir_factory: pytest.TempdirFactory,
+    tmp_path_factory: pytest.TempPathFactory,
     script_factory: ScriptFactory,
-    common_wheels: Path,
-    pip_src: Path,
+    common_wheels: pathlib.Path,
+    pip_src: pathlib.Path,
 ) -> PipTestEnvironment:
-    tmpdir = Path(str(tmpdir_factory.mktemp("script_with_launchers")))
+    tmpdir = tmp_path_factory.mktemp("script_with_launchers")
     script = script_factory(tmpdir.joinpath("workspace"))
     # Re-install pip so we get the launchers.
     script.pip_install_local("-f", common_wheels, pip_src)
@@ -112,15 +112,15 @@ def test_completion_for_supported_shells(
 
 @pytest.fixture(scope="session")
 def autocomplete_script(
-    tmpdir_factory: pytest.TempdirFactory, script_factory: ScriptFactory
+    tmp_path_factory: pytest.TempPathFactory, script_factory: ScriptFactory
 ) -> PipTestEnvironment:
-    tmpdir = Path(str(tmpdir_factory.mktemp("autocomplete_script")))
+    tmpdir = tmp_path_factory.mktemp("autocomplete_script")
     return script_factory(tmpdir.joinpath("workspace"))
 
 
 class DoAutocomplete(Protocol):
     def __call__(
-        self, words: str, cword: str, cwd: Optional[str] = None
+        self, words: str, cword: str, cwd: Union[pathlib.Path, str, None] = None
     ) -> Tuple[TestPipResult, PipTestEnvironment]:
         ...
 
@@ -133,7 +133,7 @@ def autocomplete(
     autocomplete_script.environ["PIP_AUTO_COMPLETE"] = "1"
 
     def do_autocomplete(
-        words: str, cword: str, cwd: Optional[str] = None
+        words: str, cword: str, cwd: Union[pathlib.Path, str, None] = None
     ) -> Tuple[TestPipResult, PipTestEnvironment]:
         autocomplete_script.environ["COMP_WORDS"] = words
         autocomplete_script.environ["COMP_CWORD"] = cword
diff --git a/tests/functional/test_config_settings.py b/tests/functional/test_config_settings.py
index 76c667cb91d..b914f8a25d2 100644
--- a/tests/functional/test_config_settings.py
+++ b/tests/functional/test_config_settings.py
@@ -1,9 +1,9 @@
 import json
+import pathlib
 from typing import Tuple
 from zipfile import ZipFile
 
 from tests.lib import PipTestEnvironment
-from tests.lib.path import Path
 
 PYPROJECT_TOML = """\
 [build-system]
@@ -85,7 +85,7 @@ def build_wheel(
 '''
 
 
-def make_project(path: Path) -> Tuple[str, str, Path]:
+def make_project(path: pathlib.Path) -> Tuple[str, str, pathlib.Path]:
     name = "foo"
     version = "1.0"
     project_dir = path / name
diff --git a/tests/functional/test_download.py b/tests/functional/test_download.py
index ace2ff74c5b..7284c2bcf30 100644
--- a/tests/functional/test_download.py
+++ b/tests/functional/test_download.py
@@ -1,4 +1,5 @@
 import os.path
+import pathlib
 import shutil
 import textwrap
 from hashlib import sha256
@@ -7,10 +8,8 @@
 import pytest
 
 from pip._internal.cli.status_codes import ERROR
-from pip._internal.utils.urls import path_to_url
 from tests.conftest import MockServer, ScriptFactory
 from tests.lib import PipTestEnvironment, TestData, create_really_basic_wheel
-from tests.lib.path import Path
 from tests.lib.server import file_response
 
 
@@ -27,7 +26,7 @@ def test_download_if_requested(script: PipTestEnvironment) -> None:
     It should download (in the scratch path) and not install if requested.
     """
     result = script.pip("download", "-d", "pip_downloads", "INITools==0.1")
-    result.did_create(Path("scratch") / "pip_downloads" / "INITools-0.1.tar.gz")
+    result.did_create("scratch/pip_downloads/INITools-0.1.tar.gz")
     result.did_not_create(script.site_packages / "initools")
 
 
@@ -37,7 +36,7 @@ def test_basic_download_setuptools(script: PipTestEnvironment) -> None:
     It should download (in the scratch path) and not install if requested.
     """
     result = script.pip("download", "setuptools")
-    setuptools_prefix = str(Path("scratch") / "setuptools")
+    setuptools_prefix = os.path.join("scratch", "setuptools")
     assert any(path.startswith(setuptools_prefix) for path in result.files_created)
 
 
@@ -48,7 +47,7 @@ def test_download_wheel(script: PipTestEnvironment, data: TestData) -> None:
     result = script.pip(
         "download", "--no-index", "-f", data.packages, "-d", ".", "meta"
     )
-    result.did_create(Path("scratch") / "meta-1.0-py2.py3-none-any.whl")
+    result.did_create("scratch/meta-1.0-py2.py3-none-any.whl")
     result.did_not_create(script.site_packages / "piptestpackage")
 
 
@@ -72,7 +71,7 @@ def test_single_download_from_requirements_file(script: PipTestEnvironment) -> N
         "-d",
         ".",
     )
-    result.did_create(Path("scratch") / "INITools-0.1.tar.gz")
+    result.did_create("scratch/INITools-0.1.tar.gz")
     result.did_not_create(script.site_packages / "initools")
 
 
@@ -84,8 +83,8 @@ def test_basic_download_should_download_dependencies(
     It should download dependencies (in the scratch path)
     """
     result = script.pip("download", "Paste[openid]==1.7.5.1", "-d", ".")
-    result.did_create(Path("scratch") / "Paste-1.7.5.1.tar.gz")
-    openid_tarball_prefix = str(Path("scratch") / "python-openid-")
+    result.did_create("scratch/Paste-1.7.5.1.tar.gz")
+    openid_tarball_prefix = os.path.join("scratch, python-openid-")
     assert any(path.startswith(openid_tarball_prefix) for path in result.files_created)
     result.did_not_create(script.site_packages / "openid")
 
@@ -97,7 +96,7 @@ def test_download_wheel_archive(script: PipTestEnvironment, data: TestData) -> N
     wheel_filename = "colander-0.9.9-py2.py3-none-any.whl"
     wheel_path = "/".join((data.find_links, wheel_filename))
     result = script.pip("download", wheel_path, "-d", ".", "--no-deps")
-    result.did_create(Path("scratch") / wheel_filename)
+    result.did_create(pathlib.Path("scratch", wheel_filename))
 
 
 def test_download_should_download_wheel_deps(
@@ -112,8 +111,8 @@ def test_download_should_download_wheel_deps(
     result = script.pip(
         "download", wheel_path, "-d", ".", "--find-links", data.find_links, "--no-index"
     )
-    result.did_create(Path("scratch") / wheel_filename)
-    result.did_create(Path("scratch") / dep_filename)
+    result.did_create(pathlib.Path("scratch", wheel_filename))
+    result.did_create(pathlib.Path("scratch", dep_filename))
 
 
 @pytest.mark.network
@@ -136,7 +135,7 @@ def test_download_should_skip_existing_files(script: PipTestEnvironment) -> None
         "-d",
         ".",
     )
-    result.did_create(Path("scratch") / "INITools-0.1.tar.gz")
+    result.did_create("scratch/INITools-0.1.tar.gz")
     result.did_not_create(script.site_packages / "initools")
 
     # adding second package to test-req.txt
@@ -157,9 +156,9 @@ def test_download_should_skip_existing_files(script: PipTestEnvironment) -> None
         "-d",
         ".",
     )
-    openid_tarball_prefix = str(Path("scratch") / "python-openid-")
+    openid_tarball_prefix = os.path.join("scratch", "python-openid-")
     assert any(path.startswith(openid_tarball_prefix) for path in result.files_created)
-    result.did_not_create(Path("scratch") / "INITools-0.1.tar.gz")
+    result.did_not_create("scratch/INITools-0.1.tar.gz")
     result.did_not_create(script.site_packages / "initools")
     result.did_not_create(script.site_packages / "openid")
 
@@ -172,7 +171,7 @@ def test_download_vcs_link(script: PipTestEnvironment) -> None:
     result = script.pip(
         "download", "-d", ".", "git+https://github.com/pypa/pip-test-package.git"
     )
-    result.did_create(Path("scratch") / "pip-test-package-0.1.1.zip")
+    result.did_create("scratch/pip-test-package-0.1.1.zip")
     result.did_not_create(script.site_packages / "piptestpackage")
 
 
@@ -197,7 +196,7 @@ def test_only_binary_set_then_download_specific_platform(
         "linux_x86_64",
         "fake",
     )
-    result.did_create(Path("scratch") / "fake-1.0-py2.py3-none-any.whl")
+    result.did_create("scratch/fake-1.0-py2.py3-none-any.whl")
 
 
 def test_no_deps_set_then_download_specific_platform(
@@ -221,7 +220,7 @@ def test_no_deps_set_then_download_specific_platform(
         "linux_x86_64",
         "fake",
     )
-    result.did_create(Path("scratch") / "fake-1.0-py2.py3-none-any.whl")
+    result.did_create("scratch/fake-1.0-py2.py3-none-any.whl")
 
 
 def test_download_specific_platform_fails(
@@ -295,7 +294,7 @@ def test_download_specify_platform(script: PipTestEnvironment, data: TestData) -
         "linux_x86_64",
         "fake",
     )
-    result.did_create(Path("scratch") / "fake-1.0-py2.py3-none-any.whl")
+    result.did_create("scratch/fake-1.0-py2.py3-none-any.whl")
 
     result = script.pip(
         "download",
@@ -326,7 +325,7 @@ def test_download_specify_platform(script: PipTestEnvironment, data: TestData) -
         "macosx_10_10_x86_64",
         "fake",
     )
-    result.did_create(Path("scratch") / "fake-1.0-py2.py3-none-macosx_10_9_x86_64.whl")
+    result.did_create("scratch/fake-1.0-py2.py3-none-macosx_10_9_x86_64.whl")
 
     # OSX platform wheels are not backward-compatible.
     result = script.pip(
@@ -370,7 +369,7 @@ def test_download_specify_platform(script: PipTestEnvironment, data: TestData) -
         "linux_x86_64",
         "fake==2",
     )
-    result.did_create(Path("scratch") / "fake-2.0-py2.py3-none-linux_x86_64.whl")
+    result.did_create("scratch/fake-2.0-py2.py3-none-linux_x86_64.whl")
 
     # Test with multiple supported platforms specified.
     data.reset()
@@ -391,7 +390,7 @@ def test_download_specify_platform(script: PipTestEnvironment, data: TestData) -
         "any",
         "fake==3",
     )
-    result.did_create(Path("scratch") / "fake-3.0-py2.py3-none-linux_x86_64.whl")
+    result.did_create("scratch/fake-3.0-py2.py3-none-linux_x86_64.whl")
 
 
 class TestDownloadPlatformManylinuxes:
@@ -428,7 +427,7 @@ def test_download_universal(
             platform,
             "fake",
         )
-        result.did_create(Path("scratch") / "fake-1.0-py2.py3-none-any.whl")
+        result.did_create("scratch/fake-1.0-py2.py3-none-any.whl")
 
     @pytest.mark.parametrize(
         "wheel_abi,platform",
@@ -465,7 +464,7 @@ def test_download_compatible_manylinuxes(
             platform,
             "fake",
         )
-        result.did_create(Path("scratch") / wheel)
+        result.did_create(pathlib.Path("scratch", wheel))
 
     def test_explicit_platform_only(
         self, data: TestData, script: PipTestEnvironment
@@ -508,7 +507,7 @@ def test_download__python_version(script: PipTestEnvironment, data: TestData) ->
         "2",
         "fake",
     )
-    result.did_create(Path("scratch") / "fake-1.0-py2.py3-none-any.whl")
+    result.did_create("scratch/fake-1.0-py2.py3-none-any.whl")
 
     result = script.pip(
         "download",
@@ -580,7 +579,7 @@ def test_download__python_version(script: PipTestEnvironment, data: TestData) ->
         "2",
         "fake",
     )
-    result.did_create(Path("scratch") / "fake-1.0-py2-none-any.whl")
+    result.did_create("scratch/fake-1.0-py2-none-any.whl")
 
     result = script.pip(
         "download",
@@ -607,12 +606,12 @@ def test_download__python_version(script: PipTestEnvironment, data: TestData) ->
         "3",
         "fake",
     )
-    result.did_create(Path("scratch") / "fake-2.0-py3-none-any.whl")
+    result.did_create("scratch/fake-2.0-py3-none-any.whl")
 
 
 def make_wheel_with_python_requires(
     script: PipTestEnvironment, package_name: str, python_requires: str
-) -> Path:
+) -> pathlib.Path:
     """
     Create a wheel using the given python_requires.
 
@@ -708,7 +707,7 @@ def test_download_ignore_requires_python_dont_fail_with_wrong_python(
         ".",
         "mypackage==1.0",
     )
-    result.did_create(Path("scratch") / "mypackage-1.0-py2.py3-none-any.whl")
+    result.did_create("scratch/mypackage-1.0-py2.py3-none-any.whl")
 
 
 def test_download_specify_abi(script: PipTestEnvironment, data: TestData) -> None:
@@ -731,7 +730,7 @@ def test_download_specify_abi(script: PipTestEnvironment, data: TestData) -> Non
         "fake_abi",
         "fake",
     )
-    result.did_create(Path("scratch") / "fake-1.0-py2.py3-none-any.whl")
+    result.did_create("scratch/fake-1.0-py2.py3-none-any.whl")
 
     result = script.pip(
         "download",
@@ -781,7 +780,7 @@ def test_download_specify_abi(script: PipTestEnvironment, data: TestData) -> Non
         "fakeabi",
         "fake",
     )
-    result.did_create(Path("scratch") / "fake-1.0-fk2-fakeabi-fake_platform.whl")
+    result.did_create("scratch/fake-1.0-fk2-fakeabi-fake_platform.whl")
 
     result = script.pip(
         "download",
@@ -825,7 +824,7 @@ def test_download_specify_abi(script: PipTestEnvironment, data: TestData) -> Non
         "none",
         "fake",
     )
-    result.did_create(Path("scratch") / "fake-1.0-fk2-otherabi-fake_platform.whl")
+    result.did_create("scratch/fake-1.0-fk2-otherabi-fake_platform.whl")
 
 
 def test_download_specify_implementation(
@@ -848,7 +847,7 @@ def test_download_specify_implementation(
         "fk",
         "fake",
     )
-    result.did_create(Path("scratch") / "fake-1.0-py2.py3-none-any.whl")
+    result.did_create("scratch/fake-1.0-py2.py3-none-any.whl")
 
     data.reset()
     fake_wheel(data, "fake-1.0-fk3-none-any.whl")
@@ -866,7 +865,7 @@ def test_download_specify_implementation(
         "3",
         "fake",
     )
-    result.did_create(Path("scratch") / "fake-1.0-fk3-none-any.whl")
+    result.did_create("scratch/fake-1.0-fk3-none-any.whl")
 
     result = script.pip(
         "download",
@@ -920,8 +919,8 @@ def test_download_prefer_binary_when_tarball_higher_than_wheel(
         ".",
         "source",
     )
-    result.did_create(Path("scratch") / "source-0.8-py2.py3-none-any.whl")
-    result.did_not_create(Path("scratch") / "source-1.0.tar.gz")
+    result.did_create("scratch/source-0.8-py2.py3-none-any.whl")
+    result.did_not_create("scratch/source-1.0.tar.gz")
 
 
 def test_prefer_binary_tarball_higher_than_wheel_req_file(
@@ -947,8 +946,8 @@ def test_prefer_binary_tarball_higher_than_wheel_req_file(
         ".",
     )
 
-    result.did_create(Path("scratch") / "source-0.8-py2.py3-none-any.whl")
-    result.did_not_create(Path("scratch") / "source-1.0.tar.gz")
+    result.did_create("scratch/source-0.8-py2.py3-none-any.whl")
+    result.did_not_create("scratch/source-1.0.tar.gz")
 
 
 def test_download_prefer_binary_when_wheel_doesnt_satisfy_req(
@@ -974,8 +973,8 @@ def test_download_prefer_binary_when_wheel_doesnt_satisfy_req(
         "-r",
         script.scratch_path / "test-req.txt",
     )
-    result.did_create(Path("scratch") / "source-1.0.tar.gz")
-    result.did_not_create(Path("scratch") / "source-0.8-py2.py3-none-any.whl")
+    result.did_create("scratch/source-1.0.tar.gz")
+    result.did_not_create("scratch/source-0.8-py2.py3-none-any.whl")
 
 
 def test_prefer_binary_when_wheel_doesnt_satisfy_req_req_file(
@@ -1001,8 +1000,8 @@ def test_prefer_binary_when_wheel_doesnt_satisfy_req_req_file(
         "-r",
         script.scratch_path / "test-req.txt",
     )
-    result.did_create(Path("scratch") / "source-1.0.tar.gz")
-    result.did_not_create(Path("scratch") / "source-0.8-py2.py3-none-any.whl")
+    result.did_create("scratch/source-1.0.tar.gz")
+    result.did_not_create("scratch/source-0.8-py2.py3-none-any.whl")
 
 
 def test_download_prefer_binary_when_only_tarball_exists(
@@ -1018,7 +1017,7 @@ def test_download_prefer_binary_when_only_tarball_exists(
         ".",
         "source",
     )
-    result.did_create(Path("scratch") / "source-1.0.tar.gz")
+    result.did_create("scratch/source-1.0.tar.gz")
 
 
 def test_prefer_binary_when_only_tarball_exists_req_file(
@@ -1042,22 +1041,24 @@ def test_prefer_binary_when_only_tarball_exists_req_file(
         "-r",
         script.scratch_path / "test-req.txt",
     )
-    result.did_create(Path("scratch") / "source-1.0.tar.gz")
+    result.did_create("scratch/source-1.0.tar.gz")
 
 
 @pytest.fixture(scope="session")
 def shared_script(
-    tmpdir_factory: pytest.TempdirFactory, script_factory: ScriptFactory
+    tmp_path_factory: pytest.TempPathFactory, script_factory: ScriptFactory
 ) -> PipTestEnvironment:
-    tmpdir = Path(str(tmpdir_factory.mktemp("download_shared_script")))
-    script = script_factory(tmpdir.joinpath("workspace"))
+    tmp_path = tmp_path_factory.mktemp("download_shared_script")
+    script = script_factory(tmp_path.joinpath("workspace"))
     return script
 
 
 def test_download_file_url(
-    shared_script: PipTestEnvironment, shared_data: TestData, tmpdir: Path
+    shared_script: PipTestEnvironment,
+    shared_data: TestData,
+    tmp_path: pathlib.Path,
 ) -> None:
-    download_dir = tmpdir / "download"
+    download_dir = tmp_path / "download"
     download_dir.mkdir()
     downloaded_path = download_dir / "simple-1.0.tar.gz"
 
@@ -1068,7 +1069,7 @@ def test_download_file_url(
         "-d",
         str(download_dir),
         "--no-index",
-        path_to_url(str(simple_pkg)),
+        simple_pkg.as_uri(),
     )
 
     assert downloaded_path.exists()
@@ -1076,18 +1077,19 @@ def test_download_file_url(
 
 
 def test_download_file_url_existing_ok_download(
-    shared_script: PipTestEnvironment, shared_data: TestData, tmpdir: Path
+    shared_script: PipTestEnvironment,
+    shared_data: TestData,
+    tmp_path: pathlib.Path,
 ) -> None:
-    download_dir = tmpdir / "download"
+    download_dir = tmp_path / "download"
     download_dir.mkdir()
     downloaded_path = download_dir / "simple-1.0.tar.gz"
     fake_existing_package = shared_data.packages / "simple-2.0.tar.gz"
     shutil.copy(str(fake_existing_package), str(downloaded_path))
     downloaded_path_bytes = downloaded_path.read_bytes()
-    digest = sha256(downloaded_path_bytes).hexdigest()
 
     simple_pkg = shared_data.packages / "simple-1.0.tar.gz"
-    url = "{}#sha256={}".format(path_to_url(simple_pkg), digest)
+    url = f"{simple_pkg.as_uri()}#sha256={sha256(downloaded_path_bytes).hexdigest()}"
 
     shared_script.pip("download", "-d", str(download_dir), url)
 
@@ -1095,9 +1097,11 @@ def test_download_file_url_existing_ok_download(
 
 
 def test_download_file_url_existing_bad_download(
-    shared_script: PipTestEnvironment, shared_data: TestData, tmpdir: Path
+    shared_script: PipTestEnvironment,
+    shared_data: TestData,
+    tmp_path: pathlib.Path,
 ) -> None:
-    download_dir = tmpdir / "download"
+    download_dir = tmp_path / "download"
     download_dir.mkdir()
     downloaded_path = download_dir / "simple-1.0.tar.gz"
     fake_existing_package = shared_data.packages / "simple-2.0.tar.gz"
@@ -1105,8 +1109,7 @@ def test_download_file_url_existing_bad_download(
 
     simple_pkg = shared_data.packages / "simple-1.0.tar.gz"
     simple_pkg_bytes = simple_pkg.read_bytes()
-    digest = sha256(simple_pkg_bytes).hexdigest()
-    url = "{}#sha256={}".format(path_to_url(simple_pkg), digest)
+    url = f"{simple_pkg.as_uri()}#sha256={sha256(simple_pkg_bytes).hexdigest()}"
 
     shared_script.pip("download", "-d", str(download_dir), url)
 
@@ -1116,13 +1119,13 @@ def test_download_file_url_existing_bad_download(
 def test_download_http_url_bad_hash(
     shared_script: PipTestEnvironment,
     shared_data: TestData,
-    tmpdir: Path,
+    tmp_path: pathlib.Path,
     mock_server: MockServer,
 ) -> None:
     """
     If already-downloaded file has bad checksum, re-download.
     """
-    download_dir = tmpdir / "download"
+    download_dir = tmp_path / "download"
     download_dir.mkdir()
     downloaded_path = download_dir / "simple-1.0.tar.gz"
     fake_existing_package = shared_data.packages / "simple-2.0.tar.gz"
@@ -1148,15 +1151,15 @@ def test_download_http_url_bad_hash(
 
 
 def test_download_editable(
-    script: PipTestEnvironment, data: TestData, tmpdir: Path
+    script: PipTestEnvironment, data: TestData, tmp_path: pathlib.Path
 ) -> None:
     """
     Test 'pip download' of editables in requirement file.
     """
     editable_path = str(data.src / "simplewheel-1.0").replace(os.path.sep, "/")
-    requirements_path = tmpdir / "requirements.txt"
+    requirements_path = tmp_path / "requirements.txt"
     requirements_path.write_text("-e " + editable_path + "\n")
-    download_dir = tmpdir / "download_dir"
+    download_dir = tmp_path / "download_dir"
     script.pip(
         "download", "--no-deps", "-r", str(requirements_path), "-d", str(download_dir)
     )
diff --git a/tests/functional/test_fast_deps.py b/tests/functional/test_fast_deps.py
index 87c070c78c5..0109db825b7 100644
--- a/tests/functional/test_fast_deps.py
+++ b/tests/functional/test_fast_deps.py
@@ -1,5 +1,6 @@
 import fnmatch
 import json
+import os
 import pathlib
 from os.path import basename
 from typing import Iterable
@@ -60,7 +61,7 @@ def test_download_from_pypi(
 
 @mark.network
 def test_build_wheel_with_deps(data: TestData, script: PipTestEnvironment) -> None:
-    result = pip(script, "wheel", data.packages / "requiresPaste")
+    result = pip(script, "wheel", os.fspath(data.packages / "requiresPaste"))
     created = [basename(f) for f in result.files_created]
     assert fnmatch.filter(created, "requirespaste-3.1.4-*.whl")
     assert fnmatch.filter(created, "Paste-3.4.2-*.whl")
diff --git a/tests/functional/test_freeze.py b/tests/functional/test_freeze.py
index bae9eadbd30..2897dd54ee8 100644
--- a/tests/functional/test_freeze.py
+++ b/tests/functional/test_freeze.py
@@ -1,4 +1,5 @@
 import os
+import pathlib
 import re
 import sys
 import textwrap
@@ -19,11 +20,9 @@
     need_bzr,
     need_mercurial,
     need_svn,
-    path_to_url,
     wheel,
 )
 from tests.lib.direct_url import get_created_direct_url_path
-from tests.lib.path import Path
 from tests.lib.venv import VirtualEnvironment
 
 distribute_re = re.compile("^distribute==[0-9.]+\n", re.MULTILINE)
@@ -94,9 +93,12 @@ def test_freeze_with_pip(script: PipTestEnvironment) -> None:
     assert "pip==" in result.stdout
 
 
-def test_exclude_and_normalization(script: PipTestEnvironment, tmpdir: Path) -> None:
+def test_exclude_and_normalization(
+    script: PipTestEnvironment,
+    tmp_path: pathlib.Path,
+) -> None:
     req_path = wheel.make_wheel(name="Normalizable_Name", version="1.0").save_to_dir(
-        tmpdir
+        tmp_path,
     )
     script.pip("install", "--no-index", req_path)
     result = script.pip("freeze")
@@ -150,7 +152,7 @@ def fake_install(pkgname: str, dest: str) -> None:
         "trailingdot.",
     )
     for pkgname in valid_pkgnames + invalid_pkgnames:
-        fake_install(pkgname, script.site_packages_path)
+        fake_install(pkgname, os.fspath(script.site_packages_path))
 
     result = script.pip("freeze", expect_stderr=True)
 
@@ -256,7 +258,7 @@ def test_freeze_exclude_editable(script: PipTestEnvironment) -> None:
     result = script.run(
         "git",
         "clone",
-        pkg_version,
+        os.fspath(pkg_version),
         "pip-test-package",
         expect_stderr=True,
     )
@@ -289,7 +291,7 @@ def test_freeze_git_clone(script: PipTestEnvironment) -> None:
     result = script.run(
         "git",
         "clone",
-        pkg_version,
+        os.fspath(pkg_version),
         "pip-test-package",
         expect_stderr=True,
     )
@@ -349,7 +351,7 @@ def test_freeze_git_clone_srcdir(script: PipTestEnvironment) -> None:
     result = script.run(
         "git",
         "clone",
-        pkg_version,
+        os.fspath(pkg_version),
         "pip-test-package",
         expect_stderr=True,
     )
@@ -381,7 +383,7 @@ def test_freeze_mercurial_clone_srcdir(script: PipTestEnvironment) -> None:
     # Returns path to a generated package called "version_pkg"
     pkg_version = _create_test_package_with_srcdir(script, vcs="hg")
 
-    result = script.run("hg", "clone", pkg_version, "pip-test-package")
+    result = script.run("hg", "clone", os.fspath(pkg_version), "pip-test-package")
     repo_dir = script.scratch_path / "pip-test-package"
     result = script.run("python", "setup.py", "develop", cwd=repo_dir / "subdir")
     result = script.pip("freeze")
@@ -405,7 +407,7 @@ def test_freeze_git_remote(script: PipTestEnvironment) -> None:
     result = script.run(
         "git",
         "clone",
-        pkg_version,
+        os.fspath(pkg_version),
         "pip-test-package",
         expect_stderr=True,
     )
@@ -427,7 +429,7 @@ def test_freeze_git_remote(script: PipTestEnvironment) -> None:
             ...
         """
         )
-        .format(remote=path_to_url(origin_remote))
+        .format(remote=origin_remote.as_uri())
         .strip()
     )
     _check_output(result.stdout, expected)
@@ -441,13 +443,13 @@ def test_freeze_git_remote(script: PipTestEnvironment) -> None:
             ...
         """
         )
-        .format(remote=path_to_url(origin_remote))
+        .format(remote=origin_remote.as_uri())
         .strip()
     )
     _check_output(result.stdout, expected)
     # When the remote is a local path, it must exist.
     # If it doesn't, it gets flagged as invalid.
-    other_remote = pkg_version + "-other"
+    other_remote = f"{pkg_version}-other"
     script.run("git", "remote", "set-url", "other", other_remote, cwd=repo_dir)
     result = script.pip("freeze", expect_stderr=True)
     expected = os.path.normcase(
@@ -462,7 +464,7 @@ def test_freeze_git_remote(script: PipTestEnvironment) -> None:
     _check_output(os.path.normcase(result.stdout), expected)
     # when there are more than one origin, priority is given to the
     # remote named origin
-    script.run("git", "remote", "add", "origin", origin_remote, cwd=repo_dir)
+    script.run("git", "remote", "add", "origin", os.fspath(origin_remote), cwd=repo_dir)
     result = script.pip("freeze", expect_stderr=True)
     expected = (
         textwrap.dedent(
@@ -471,7 +473,7 @@ def test_freeze_git_remote(script: PipTestEnvironment) -> None:
             ...
         """
         )
-        .format(remote=path_to_url(origin_remote))
+        .format(remote=origin_remote.as_uri())
         .strip()
     )
     _check_output(result.stdout, expected)
@@ -489,7 +491,7 @@ def test_freeze_mercurial_clone(script: PipTestEnvironment) -> None:
     result = script.run(
         "hg",
         "clone",
-        pkg_version,
+        os.fspath(pkg_version),
         "pip-test-package",
         expect_stderr=True,
     )
@@ -522,7 +524,7 @@ def test_freeze_bazaar_clone(script: PipTestEnvironment) -> None:
     except OSError as e:
         pytest.fail(f"Invoking `bzr` failed: {e}")
 
-    result = script.run("bzr", "checkout", checkout_path, "bzr-package")
+    result = script.run("bzr", "checkout", os.fspath(checkout_path), "bzr-package")
     result = script.run(
         "python",
         "setup.py",
@@ -562,7 +564,13 @@ def test_freeze_nested_vcs(
     # Clone Python package into inner directory and install it.
     src_path = root_path.joinpath("src")
     src_path.mkdir()
-    script.run(inner_vcs, "clone", pkg_path, src_path, expect_stderr=True)
+    script.run(
+        inner_vcs,
+        "clone",
+        os.fspath(pkg_path),
+        os.fspath(src_path),
+        expect_stderr=True,
+    )
     script.pip("install", "-e", src_path, expect_stderr=True)
 
     # Check the freeze output recognizes the inner VCS.
@@ -600,7 +608,7 @@ def test_freeze_with_requirement_option_file_url_egg_not_installed(
     is not installed.
     """
 
-    url = path_to_url("my-package.tar.gz") + "#egg=Does.Not-Exist"
+    url = pathlib.Path("my-package.tar.gz").resolve().as_uri() + "#egg=Does.Not-Exist"
     requirements_path = script.scratch_path.joinpath("requirements.txt")
     requirements_path.write_text(url + "\n")
 
@@ -878,14 +886,18 @@ def test_freeze_user(
 
 
 @pytest.mark.network
-def test_freeze_path(tmpdir: Path, script: PipTestEnvironment, data: TestData) -> None:
+def test_freeze_path(
+    tmp_path: pathlib.Path,
+    script: PipTestEnvironment,
+    data: TestData,
+) -> None:
     """
     Test freeze with --path.
     """
     script.pip(
-        "install", "--find-links", data.find_links, "--target", tmpdir, "simple==2.0"
+        "install", "--find-links", data.find_links, "--target", tmp_path, "simple==2.0"
     )
-    result = script.pip("freeze", "--path", tmpdir)
+    result = script.pip("freeze", "--path", tmp_path)
     expected = textwrap.dedent(
         """\
         simple==2.0
@@ -897,7 +909,7 @@ def test_freeze_path(tmpdir: Path, script: PipTestEnvironment, data: TestData) -
 @pytest.mark.network
 @pytest.mark.incompatible_with_test_venv
 def test_freeze_path_exclude_user(
-    tmpdir: Path, script: PipTestEnvironment, data: TestData
+    tmp_path: pathlib.Path, script: PipTestEnvironment, data: TestData
 ) -> None:
     """
     Test freeze with --path and make sure packages from --user are not picked
@@ -905,7 +917,7 @@ def test_freeze_path_exclude_user(
     """
     script.pip_install_local("--find-links", data.find_links, "--user", "simple2")
     script.pip(
-        "install", "--find-links", data.find_links, "--target", tmpdir, "simple==1.0"
+        "install", "--find-links", data.find_links, "--target", tmp_path, "simple==1.0"
     )
     result = script.pip("freeze", "--user")
     expected = textwrap.dedent(
@@ -914,7 +926,7 @@ def test_freeze_path_exclude_user(
         <BLANKLINE>"""
     )
     _check_output(result.stdout, expected)
-    result = script.pip("freeze", "--path", tmpdir)
+    result = script.pip("freeze", "--path", tmp_path)
     expected = textwrap.dedent(
         """\
         simple==1.0
@@ -925,14 +937,14 @@ def test_freeze_path_exclude_user(
 
 @pytest.mark.network
 def test_freeze_path_multiple(
-    tmpdir: Path, script: PipTestEnvironment, data: TestData
+    tmp_path: pathlib.Path, script: PipTestEnvironment, data: TestData
 ) -> None:
     """
     Test freeze with multiple --path arguments.
     """
-    path1 = tmpdir / "path1"
+    path1 = tmp_path / "path1"
     os.mkdir(path1)
-    path2 = tmpdir / "path2"
+    path2 = tmp_path / "path2"
     os.mkdir(path2)
     script.pip(
         "install", "--find-links", data.find_links, "--target", path1, "simple==2.0"
@@ -961,8 +973,7 @@ def test_freeze_path_multiple(
 def test_freeze_direct_url_archive(
     script: PipTestEnvironment, shared_data: TestData
 ) -> None:
-    req = "simple @ " + path_to_url(shared_data.packages / "simple-2.0.tar.gz")
-    assert req.startswith("simple @ file://")
+    req = "simple @ " + shared_data.packages.joinpath("simple-2.0.tar.gz").as_uri()
     script.pip("install", req)
     result = script.pip("freeze")
     assert req in result.stdout
diff --git a/tests/functional/test_hash.py b/tests/functional/test_hash.py
index 7734ce58bb1..ee40adec591 100644
--- a/tests/functional/test_hash.py
+++ b/tests/functional/test_hash.py
@@ -1,39 +1,44 @@
 """Tests for the ``pip hash`` command"""
+import pathlib
+
 from tests.lib import PipTestEnvironment
-from tests.lib.path import Path
 
 
-def test_basic_hash(script: PipTestEnvironment, tmpdir: Path) -> None:
+def test_basic_hash(script: PipTestEnvironment, tmp_path: pathlib.Path) -> None:
     """Run 'pip hash' through its default behavior."""
     expected = (
         "--hash=sha256:2cf24dba5fb0a30e26e83b2ac5b9e29e1b161e5c1fa7425"
         "e73043362938b9824"
     )
-    result = script.pip("hash", _hello_file(tmpdir))
+    result = script.pip("hash", _hello_file(tmp_path))
     assert expected in str(result)
 
 
-def test_good_algo_option(script: PipTestEnvironment, tmpdir: Path) -> None:
+def test_good_algo_option(script: PipTestEnvironment, tmp_path: pathlib.Path) -> None:
     """Make sure the -a option works."""
     expected = (
         "--hash=sha512:9b71d224bd62f3785d96d46ad3ea3d73319bfbc2890caad"
         "ae2dff72519673ca72323c3d99ba5c11d7c7acc6e14b8c5da0c4663475c2e"
         "5c3adef46f73bcdec043"
     )
-    result = script.pip("hash", "-a", "sha512", _hello_file(tmpdir))
+    result = script.pip("hash", "-a", "sha512", _hello_file(tmp_path))
     assert expected in str(result)
 
 
-def test_bad_algo_option(script: PipTestEnvironment, tmpdir: Path) -> None:
+def test_bad_algo_option(script: PipTestEnvironment, tmp_path: pathlib.Path) -> None:
     """Make sure the -a option raises an error when given a bad operand."""
     result = script.pip(
-        "hash", "-a", "invalidname", _hello_file(tmpdir), expect_error=True
+        "hash",
+        "-a",
+        "invalidname",
+        _hello_file(tmp_path),
+        expect_error=True,
     )
     assert "invalid choice: 'invalidname'" in str(result)
 
 
-def _hello_file(tmpdir: Path) -> Path:
+def _hello_file(tmp_path: pathlib.Path) -> pathlib.Path:
     """Return a temp file to hash containing "hello"."""
-    file = tmpdir / "hashable"
+    file = tmp_path / "hashable"
     file.write_text("hello")
     return file
diff --git a/tests/functional/test_install.py b/tests/functional/test_install.py
index 3bf2579ed4b..186a3787cef 100644
--- a/tests/functional/test_install.py
+++ b/tests/functional/test_install.py
@@ -1,6 +1,6 @@
 import distutils
-import glob
 import os
+import pathlib
 import re
 import ssl
 import sys
@@ -25,12 +25,10 @@
     need_bzr,
     need_mercurial,
     need_svn,
-    path_to_url,
     pyversion,
     requirements_file,
 )
 from tests.lib.local_repos import local_checkout
-from tests.lib.path import Path
 from tests.lib.server import (
     file_response,
     make_mock_server,
@@ -44,7 +42,7 @@
 def test_pep518_uses_build_env(
     script: PipTestEnvironment,
     data: TestData,
-    common_wheels: Path,
+    common_wheels: pathlib.Path,
     command: str,
     variant: str,
 ) -> None:
@@ -70,8 +68,8 @@ def test_pep518_uses_build_env(
 def test_pep518_build_env_uses_same_pip(
     script: PipTestEnvironment,
     data: TestData,
-    pip_src: Path,
-    common_wheels: Path,
+    pip_src: pathlib.Path,
+    common_wheels: pathlib.Path,
     deprecated_python: bool,
 ) -> None:
     """Ensure the subprocess call to pip for installing the
@@ -81,14 +79,14 @@ def test_pep518_build_env_uses_same_pip(
         fp.write("raise ImportError")
     script.run(
         "python",
-        pip_src / "src/pip",
+        os.fspath(pip_src / "src/pip"),
         "install",
         "--no-index",
         "-f",
-        common_wheels,
+        os.fspath(common_wheels),
         "-f",
-        data.packages,
-        data.src.joinpath("pep518-3.0"),
+        os.fspath(data.packages),
+        os.fspath(data.src.joinpath("pep518-3.0")),
         expect_stderr=deprecated_python,
     )
 
@@ -108,14 +106,14 @@ def test_pep518_refuses_conflicting_requires(
             "Some build dependencies for {url} conflict "
             "with PEP 517/518 supported "
             "requirements: setuptools==1.0 is incompatible with "
-            "setuptools>=40.8.0.".format(url=path_to_url(project_dir))
+            "setuptools>=40.8.0.".format(url=project_dir.as_uri())
         )
         in result.stderr
     ), str(result)
 
 
 def test_pep518_refuses_invalid_requires(
-    script: PipTestEnvironment, data: TestData, common_wheels: Path
+    script: PipTestEnvironment, data: TestData, common_wheels: pathlib.Path
 ) -> None:
     result = script.pip(
         "install",
@@ -134,7 +132,7 @@ def test_pep518_refuses_invalid_requires(
 
 
 def test_pep518_refuses_invalid_build_system(
-    script: PipTestEnvironment, data: TestData, common_wheels: Path
+    script: PipTestEnvironment, data: TestData, common_wheels: pathlib.Path
 ) -> None:
     result = script.pip(
         "install",
@@ -153,7 +151,7 @@ def test_pep518_refuses_invalid_build_system(
 
 
 def test_pep518_allows_missing_requires(
-    script: PipTestEnvironment, data: TestData, common_wheels: Path
+    script: PipTestEnvironment, data: TestData, common_wheels: pathlib.Path
 ) -> None:
     result = script.pip(
         "install",
@@ -174,7 +172,10 @@ def test_pep518_allows_missing_requires(
 
 @pytest.mark.incompatible_with_test_venv
 def test_pep518_with_user_pip(
-    script: PipTestEnvironment, pip_src: Path, data: TestData, common_wheels: Path
+    script: PipTestEnvironment,
+    pip_src: pathlib.Path,
+    data: TestData,
+    common_wheels: pathlib.Path,
 ) -> None:
     """
     Check that build dependencies are installed into the build
@@ -203,7 +204,7 @@ def test_pep518_with_user_pip(
 
 
 def test_pep518_with_extra_and_markers(
-    script: PipTestEnvironment, data: TestData, common_wheels: Path
+    script: PipTestEnvironment, data: TestData, common_wheels: pathlib.Path
 ) -> None:
     script.pip(
         "wheel",
@@ -217,7 +218,7 @@ def test_pep518_with_extra_and_markers(
 
 
 def test_pep518_with_namespace_package(
-    script: PipTestEnvironment, data: TestData, common_wheels: Path
+    script: PipTestEnvironment, data: TestData, common_wheels: pathlib.Path
 ) -> None:
     script.pip(
         "wheel",
@@ -239,7 +240,7 @@ def test_pep518_with_namespace_package(
 def test_pep518_forkbombs(
     script: PipTestEnvironment,
     data: TestData,
-    common_wheels: Path,
+    common_wheels: pathlib.Path,
     command: str,
     package: str,
 ) -> None:
@@ -258,7 +259,7 @@ def test_pep518_forkbombs(
     assert (
         "{1} is already being built: {0} from {1}".format(
             package,
-            path_to_url(package_source),
+            package_source.as_uri(),
         )
         in result.stderr
     ), str(result)
@@ -268,9 +269,9 @@ def test_pep518_forkbombs(
 @pytest.mark.usefixtures("with_wheel")
 def test_pip_second_command_line_interface_works(
     script: PipTestEnvironment,
-    pip_src: Path,
+    pip_src: pathlib.Path,
     data: TestData,
-    common_wheels: Path,
+    common_wheels: pathlib.Path,
     deprecated_python: bool,
 ) -> None:
     """
@@ -280,7 +281,7 @@ def test_pip_second_command_line_interface_works(
     script.pip_install_local("-f", common_wheels, pip_src)
     args = [f"pip{pyversion}"]
     args.extend(["install", "INITools==0.2"])
-    args.extend(["-f", data.packages])
+    args.extend(["-f", os.fspath(data.packages)])
     result = script.run(*args)
     dist_info_folder = script.site_packages / "INITools-0.2.dist-info"
     initools_folder = script.site_packages / "initools"
@@ -359,7 +360,7 @@ def _test_install_editable_from_git(script: PipTestEnvironment) -> None:
     args = [
         "install",
         "-e",
-        "git+{url}#egg=testpackage".format(url=path_to_url(pkg_path)),
+        f"git+{pkg_path.as_uri()}#egg=testpackage",
     ]
     result = script.pip(*args)
     result.assert_installed("testpackage", with_files=[".git"])
@@ -376,7 +377,7 @@ def test_install_editable_from_git_autobuild_wheel(script: PipTestEnvironment) -
 
 @pytest.mark.network
 def test_install_editable_uninstalls_existing(
-    data: TestData, script: PipTestEnvironment, tmpdir: Path
+    data: TestData, script: PipTestEnvironment, tmp_path: pathlib.Path
 ) -> None:
     """
     Test that installing an editable uninstalls a previously installed
@@ -395,7 +396,7 @@ def test_install_editable_uninstalls_existing(
         "{dir}#egg=pip-test-package".format(
             dir=local_checkout(
                 "git+https://github.com/pypa/pip-test-package.git",
-                tmpdir,
+                tmp_path,
             )
         ),
     )
@@ -436,7 +437,7 @@ def test_install_editable_uninstalls_existing_from_path(
 def test_basic_install_editable_from_hg(script: PipTestEnvironment) -> None:
     """Test cloning and hg+file install from Mercurial."""
     pkg_path = _create_test_package(script, name="testpackage", vcs="hg")
-    url = "hg+{}#egg=testpackage".format(path_to_url(pkg_path))
+    url = f"hg+{pkg_path.as_uri()}#egg=testpackage"
     assert url.startswith("hg+file")
     args = ["install", "-e", url]
     result = script.pip(*args)
@@ -452,7 +453,7 @@ def test_vcs_url_final_slash_normalization(script: PipTestEnvironment) -> None:
     args = [
         "install",
         "-e",
-        "hg+{url}/#egg=testpackage".format(url=path_to_url(pkg_path)),
+        f"hg+{pkg_path.as_uri()}/#egg=testpackage",
     ]
     result = script.pip(*args)
     result.assert_installed("testpackage", with_files=[".hg"])
@@ -465,7 +466,7 @@ def test_install_editable_from_bazaar(script: PipTestEnvironment) -> None:
     args = [
         "install",
         "-e",
-        "bzr+{url}/#egg=testpackage".format(url=path_to_url(pkg_path)),
+        f"bzr+{pkg_path.as_uri()}/#egg=testpackage",
     ]
     result = script.pip(*args)
     result.assert_installed("testpackage", with_files=[".bzr"])
@@ -474,7 +475,7 @@ def test_install_editable_from_bazaar(script: PipTestEnvironment) -> None:
 @pytest.mark.network
 @need_bzr
 def test_vcs_url_urlquote_normalization(
-    script: PipTestEnvironment, tmpdir: Path
+    script: PipTestEnvironment, tmp_path: pathlib.Path
 ) -> None:
     """
     Test that urlquoted characters are normalized for repo URL comparison.
@@ -487,7 +488,7 @@ def test_vcs_url_urlquote_normalization(
                 "bzr+http://bazaar.launchpad.net/"
                 "%7Edjango-wikiapp/django-wikiapp"
                 "/release-0.1",
-                tmpdir,
+                tmp_path,
             )
         ),
     )
@@ -504,8 +505,7 @@ def test_basic_install_from_local_directory(
     args = ["install"]
     if resolver:
         args.append(resolver)
-    to_install = data.packages.joinpath("FSPkg")
-    args.append(to_install)
+    args.append(os.fspath(data.packages.joinpath("FSPkg")))
     result = script.pip(*args)
     fspkg_folder = script.site_packages / "fspkg"
     dist_info_folder = script.site_packages / "FSPkg-0.1.dev0.dist-info"
@@ -536,16 +536,14 @@ def test_basic_install_relative_directory(
     package_folder = script.site_packages / "fspkg"
 
     # Compute relative install path to FSPkg from scratch path.
-    full_rel_path = Path(
-        os.path.relpath(data.packages.joinpath("FSPkg"), script.scratch_path)
-    )
-    full_rel_url = "file:" + full_rel_path.replace(os.path.sep, "/") + "#egg=FSPkg"
+    full_rel_path = data.packages.joinpath("FSPkg").relative_to(script.scratch_path)
+    full_rel_url = f"{full_rel_path.as_uri()}#egg=FSPkg"
     embedded_rel_path = script.scratch_path.joinpath(full_rel_path)
 
     req_path = {
-        "rel_path": full_rel_path,
+        "rel_path": os.fspath(full_rel_path),
         "rel_url": full_rel_url,
-        "embedded_rel_path": embedded_rel_path,
+        "embedded_rel_path": os.fspath(embedded_rel_path),
     }[test_type]
 
     # Install as either editable or not.
@@ -574,7 +572,7 @@ def test_install_quiet(script: PipTestEnvironment, data: TestData) -> None:
 
 
 def test_hashed_install_success(
-    script: PipTestEnvironment, data: TestData, tmpdir: Path
+    script: PipTestEnvironment, data: TestData, tmp_path: pathlib.Path
 ) -> None:
     """
     Test that installing various sorts of requirements with correct hashes
@@ -584,18 +582,20 @@ def test_hashed_install_success(
     scenes).
 
     """
-    file_url = path_to_url((data.packages / "simple-1.0.tar.gz").resolve())
+    file_url = data.packages.joinpath("simple-1.0.tar.gz").resolve().as_uri()
     with requirements_file(
         "simple2==1.0 --hash=sha256:9336af72ca661e6336eb87bc7de3e8844d853e"
         "3848c2b9bbd2e8bf01db88c2c7\n"
         "{simple} --hash=sha256:393043e672415891885c9a2a0929b1af95fb866d6c"
         "a016b42d2e6ce53619b653".format(simple=file_url),
-        tmpdir,
+        tmp_path,
     ) as reqs_file:
         script.pip_install_local("-r", reqs_file.resolve())
 
 
-def test_hashed_install_failure(script: PipTestEnvironment, tmpdir: Path) -> None:
+def test_hashed_install_failure(
+    script: PipTestEnvironment, tmp_path: pathlib.Path
+) -> None:
     """Test that wrong hashes stop installation.
 
     This makes sure prepare_files() is called in the course of installation
@@ -606,7 +606,7 @@ def test_hashed_install_failure(script: PipTestEnvironment, tmpdir: Path) -> Non
     with requirements_file(
         "simple2==1.0 --hash=sha256:9336af72ca661e6336eb87b"
         "c7de3e8844d853e3848c2b9bbd2e8bf01db88c2c\n",
-        tmpdir,
+        tmp_path,
     ) as reqs_file:
         result = script.pip_install_local("-r", reqs_file.resolve(), expect_error=True)
     assert len(result.files_created) == 0
@@ -619,7 +619,7 @@ def assert_re_match(pattern: str, text: str) -> None:
 @pytest.mark.network
 @pytest.mark.skip("Fails on new resolver")
 def test_hashed_install_failure_later_flag(
-    script: PipTestEnvironment, tmpdir: Path
+    script: PipTestEnvironment, tmp_path: pathlib.Path
 ) -> None:
     with requirements_file(
         "blessings==1.0\n"
@@ -628,7 +628,7 @@ def test_hashed_install_failure_later_flag(
         "more-itertools-1.0.tar.gz#md5=b21850c3cfa7efbb70fd662ab5413bdd\n"
         "https://files.pythonhosted.org/"
         "packages/source/p/peep/peep-3.1.1.tar.gz\n",
-        tmpdir,
+        tmp_path,
     ) as reqs_file:
         result = script.pip("install", "-r", reqs_file.resolve(), expect_error=True)
 
@@ -654,11 +654,10 @@ def test_install_from_local_directory_with_in_tree_build(
     Test installing from a local directory with default in tree build.
     """
     to_install = data.packages.joinpath("FSPkg")
-    args = ["install", to_install]
 
     in_tree_build_dir = to_install / "build"
     assert not in_tree_build_dir.exists()
-    result = script.pip(*args)
+    result = script.pip("install", to_install)
     fspkg_folder = script.site_packages / "fspkg"
     dist_info_folder = script.site_packages / "FSPkg-0.1.dev0.dist-info"
     result.did_create(fspkg_folder)
@@ -799,14 +798,14 @@ def test_install_with_hacked_egg_info(
 
 @pytest.mark.network
 def test_install_using_install_option_and_editable(
-    script: PipTestEnvironment, tmpdir: Path
+    script: PipTestEnvironment, tmp_path: pathlib.Path
 ) -> None:
     """
     Test installing a tool using -e and --install-option
     """
     folder = "script_folder"
     script.scratch_path.joinpath(folder).mkdir()
-    url = local_checkout("git+https://github.com/pypa/pip-test-package", tmpdir)
+    url = local_checkout("git+https://github.com/pypa/pip-test-package", tmp_path)
     result = script.pip(
         "install",
         "-e",
@@ -825,7 +824,7 @@ def test_install_using_install_option_and_editable(
 @pytest.mark.network
 @need_mercurial
 def test_install_global_option_using_editable(
-    script: PipTestEnvironment, tmpdir: Path
+    script: PipTestEnvironment, tmp_path: pathlib.Path
 ) -> None:
     """
     Test using global distutils options, but in an editable installation
@@ -835,7 +834,7 @@ def test_install_global_option_using_editable(
         "install",
         "--global-option=--version",
         "-e",
-        "{url}@0.2.5#egg=anyjson".format(url=local_checkout(url, tmpdir)),
+        f"{local_checkout(url, tmp_path)}@0.2.5#egg=anyjson",
         expect_stderr=True,
     )
     assert "Successfully installed anyjson" in result.stdout
@@ -896,7 +895,7 @@ def test_install_folder_using_relative_path(script: PipTestEnvironment) -> None:
     script.scratch_path.joinpath("initools", "mock").mkdir()
     pkg_path = script.scratch_path / "initools" / "mock"
     pkg_path.joinpath("setup.py").write_text(mock100_setup_py)
-    result = script.pip("install", Path("initools") / "mock")
+    result = script.pip("install", "./initools/mock")
     dist_info_folder = script.site_packages / "mock-100.1.dist-info"
     result.did_create(dist_info_folder)
 
@@ -921,7 +920,7 @@ def test_install_package_with_target(script: PipTestEnvironment) -> None:
     """
     target_dir = script.scratch_path / "target"
     result = script.pip_install_local("-t", target_dir, "simple==1.0")
-    result.did_create(Path("scratch") / "target" / "simple")
+    result.did_create("scratch/target/simple")
 
     # Test repeated call without --upgrade, no files should have changed
     result = script.pip_install_local(
@@ -930,23 +929,21 @@ def test_install_package_with_target(script: PipTestEnvironment) -> None:
         "simple==1.0",
         expect_stderr=True,
     )
-    result.did_not_update(Path("scratch") / "target" / "simple")
+    result.did_not_update("scratch/target/simple")
 
     # Test upgrade call, check that new version is installed
     result = script.pip_install_local("--upgrade", "-t", target_dir, "simple==2.0")
-    result.did_update(Path("scratch") / "target" / "simple")
-    dist_info_folder = Path("scratch") / "target" / "simple-2.0.dist-info"
-    result.did_create(dist_info_folder)
+    result.did_update("scratch/target/simple")
+    result.did_create("scratch/target/simple-2.0.dist-info")
 
     # Test install and upgrade of single-module package
     result = script.pip_install_local("-t", target_dir, "singlemodule==0.0.0")
-    singlemodule_py = Path("scratch") / "target" / "singlemodule.py"
-    result.did_create(singlemodule_py)
+    result.did_create("scratch/target/singlemodule.py")
 
     result = script.pip_install_local(
         "-t", target_dir, "singlemodule==0.0.1", "--upgrade"
     )
-    result.did_update(singlemodule_py)
+    result.did_update("scratch/target/singlemodule.py")
 
 
 @pytest.mark.parametrize("target_option", ["--target", "-t"])
@@ -988,8 +985,7 @@ def test_install_nonlocal_compatible_wheel(
     )
     assert result.returncode == SUCCESS
 
-    distinfo = Path("scratch") / "target" / "simplewheel-2.0-1.dist-info"
-    result.did_create(distinfo)
+    result.did_create("scratch/target/simplewheel-2.0-1.dist-info")
 
     # Test install without --target
     result = script.pip(
@@ -1024,23 +1020,21 @@ def test_install_nonlocal_compatible_wheel_path(
         target_dir,
         "--no-index",
         "--only-binary=:all:",
-        Path(data.packages) / "simplewheel-2.0-py3-fakeabi-fakeplat.whl",
+        data.packages / "simplewheel-2.0-py3-fakeabi-fakeplat.whl",
         expect_error=(resolver_variant == "2020-resolver"),
     )
     if resolver_variant == "2020-resolver":
         assert result.returncode == ERROR
     else:
         assert result.returncode == SUCCESS
-
-        distinfo = Path("scratch") / "target" / "simplewheel-2.0.dist-info"
-        result.did_create(distinfo)
+        result.did_create("scratch/target/simplewheel-2.0.dist-info")
 
     # Test a full path requirement (without --target)
     result = script.pip(
         "install",
         "--no-index",
         "--only-binary=:all:",
-        Path(data.packages) / "simplewheel-2.0-py3-fakeabi-fakeplat.whl",
+        data.packages / "simplewheel-2.0-py3-fakeabi-fakeplat.whl",
         expect_error=True,
     )
     assert result.returncode == ERROR
@@ -1399,7 +1393,7 @@ def test_compiles_pyc(script: PipTestEnvironment) -> None:
     #   any of them
     exists = [
         os.path.exists(script.site_packages_path / "initools/__init__.pyc"),
-        *glob.glob(script.site_packages_path / "initools/__pycache__/__init__*.pyc"),
+        *script.site_packages_path.glob("initools/__pycache__/__init__*.pyc"),
     ]
 
     assert any(exists)
@@ -1417,7 +1411,7 @@ def test_no_compiles_pyc(script: PipTestEnvironment) -> None:
     #   any of them
     exists = [
         os.path.exists(script.site_packages_path / "initools/__init__.pyc"),
-        *glob.glob(script.site_packages_path / "initools/__pycache__/__init__*.pyc"),
+        *script.site_packages_path.glob("initools/__pycache__/__init__*.pyc"),
     ]
 
     assert not any(exists)
@@ -1461,7 +1455,7 @@ def test_install_upgrade_editable_depending_on_other_editable(
 def test_install_subprocess_output_handling(
     script: PipTestEnvironment, data: TestData
 ) -> None:
-    args = ["install", data.src.joinpath("chattymodule")]
+    args = ["install", os.fspath(data.src.joinpath("chattymodule"))]
 
     # Regular install should not show output from the chatty setup.py
     result = script.pip(*args)
@@ -1486,11 +1480,14 @@ def test_install_subprocess_output_handling(
     assert 1 == result.stderr.count("I DIE, I DIE")
 
 
-def test_install_log(script: PipTestEnvironment, data: TestData, tmpdir: Path) -> None:
+def test_install_log(
+    script: PipTestEnvironment,
+    data: TestData,
+    tmp_path: pathlib.Path,
+) -> None:
     # test that verbose logs go to "--log" file
-    f = tmpdir.joinpath("log.txt")
-    args = [f"--log={f}", "install", data.src.joinpath("chattymodule")]
-    result = script.pip(*args)
+    f = tmp_path.joinpath("log.txt")
+    result = script.pip(f"--log={f}", "install", data.src.joinpath("chattymodule"))
     assert 0 == result.stdout.count("HELLO FROM CHATTYMODULE")
     with open(f) as fp:
         # one from egg_info, one from install
@@ -1498,11 +1495,10 @@ def test_install_log(script: PipTestEnvironment, data: TestData, tmpdir: Path) -
 
 
 def test_install_topological_sort(script: PipTestEnvironment, data: TestData) -> None:
-    args = ["install", "TopoRequires4", "--no-index", "-f", data.packages]
-    res = str(script.pip(*args))
+    res = script.pip("install", "TopoRequires4", "--no-index", "-f", data.packages)
     order1 = "TopoRequires, TopoRequires2, TopoRequires3, TopoRequires4"
     order2 = "TopoRequires, TopoRequires3, TopoRequires2, TopoRequires4"
-    assert order1 in res or order2 in res, res
+    assert order1 in res.stdout or order2 in res.stdout, str(res)
 
 
 @pytest.mark.usefixtures("with_wheel")
@@ -1624,10 +1620,10 @@ def test_install_no_binary_builds_pep_517_wheel(
 @pytest.mark.network
 @pytest.mark.usefixtures("with_wheel")
 def test_install_no_binary_uses_local_backend(
-    script: PipTestEnvironment, data: TestData, tmpdir: Path
+    script: PipTestEnvironment, data: TestData, tmp_path: pathlib.Path
 ) -> None:
     to_install = data.packages.joinpath("pep517_wrapper_buildsys")
-    script.environ["PIP_TEST_MARKER_FILE"] = marker = str(tmpdir / "marker")
+    script.environ["PIP_TEST_MARKER_FILE"] = marker = str(tmp_path / "marker")
     res = script.pip("install", "--no-binary=:all:", "-f", data.find_links, to_install)
     expected = "Successfully installed pep517-wrapper-buildsys"
     # Must have installed the package
@@ -1916,15 +1912,18 @@ def test_installed_files_recorded_in_deterministic_order(
     """
     to_install = data.packages.joinpath("FSPkg")
     result = script.pip("install", to_install)
-    fspkg_folder = script.site_packages / "fspkg"
+    fspkg_folder = script.site_packages_path / "fspkg"
     egg_info = f"FSPkg-0.1.dev0-py{pyversion}.egg-info"
-    installed_files_path = script.site_packages / egg_info / "installed-files.txt"
+    installed_files_path = script.site_packages_path.joinpath(
+        egg_info,
+        "installed-files.txt",
+    )
     result.did_create(fspkg_folder)
     result.did_create(installed_files_path)
 
     installed_files_path = result.files_created[installed_files_path].full
     installed_files_lines = [
-        p for p in Path(installed_files_path).read_text().split("\n") if p
+        p for p in installed_files_path.read_text().split("\n") if p
     ]
     assert installed_files_lines == sorted(installed_files_lines)
 
@@ -1987,8 +1986,7 @@ def test_target_install_ignores_distutils_config_install_prefix(
     script: PipTestEnvironment,
 ) -> None:
     prefix = script.scratch_path / "prefix"
-    distutils_config = Path(
-        os.path.expanduser("~"),
+    distutils_config = pathlib.Path.home().joinpath(
         "pydistutils.cfg" if sys.platform == "win32" else ".pydistutils.cfg",
     )
     distutils_config.write_text(
@@ -2164,7 +2162,7 @@ def test_install_sends_client_cert(
                 "simple-3.0.tar.gz": "/files/simple-3.0.tar.gz",
             }
         ),
-        file_response(str(data.packages / "simple-3.0.tar.gz")),
+        file_response(data.packages / "simple-3.0.tar.gz"),
     ]
 
     url = f"https://{server.host}:{server.port}/simple"
diff --git a/tests/functional/test_install_cleanup.py b/tests/functional/test_install_cleanup.py
index c0ea5a425b9..dbe11497400 100644
--- a/tests/functional/test_install_cleanup.py
+++ b/tests/functional/test_install_cleanup.py
@@ -1,5 +1,3 @@
-from os.path import exists
-
 import pytest
 
 from tests.lib import PipTestEnvironment, TestData
@@ -27,7 +25,7 @@ def test_no_clean_option_blocks_cleaning_after_install(
         #       remove it when removing support for --build
         allow_stderr_warning=True,
     )
-    assert exists(build)
+    assert build.exists()
 
 
 @pytest.mark.network
@@ -36,7 +34,13 @@ def test_pep517_no_legacy_cleanup(script: PipTestEnvironment, data: TestData) ->
     """Test a PEP 517 failed build does not attempt a legacy cleanup"""
     to_install = data.packages.joinpath("pep517_wrapper_buildsys")
     script.environ["PIP_TEST_FAIL_BUILD_WHEEL"] = "1"
-    res = script.pip("install", "-f", data.find_links, to_install, expect_error=True)
+    res = script.pip(
+        "install",
+        "-f",
+        data.find_links,
+        to_install,
+        expect_error=True,
+    )
     # Must not have built the package
     expected = "Failed building wheel for pep517-wrapper-buildsys"
     assert expected in str(res)
diff --git a/tests/functional/test_install_config.py b/tests/functional/test_install_config.py
index 2e4bb742785..26eab3df946 100644
--- a/tests/functional/test_install_config.py
+++ b/tests/functional/test_install_config.py
@@ -284,12 +284,8 @@ def test_prompt_for_authentication(
 
     server = make_mock_server(ssl_context=ctx)
     server.mock.side_effect = [
-        package_page(
-            {
-                "simple-3.0.tar.gz": "/files/simple-3.0.tar.gz",
-            }
-        ),
-        authorization_response(str(data.packages / "simple-3.0.tar.gz")),
+        package_page({"simple-3.0.tar.gz": "/files/simple-3.0.tar.gz"}),
+        authorization_response(data.packages / "simple-3.0.tar.gz"),
     ]
 
     url = f"https://{server.host}:{server.port}/simple"
@@ -325,12 +321,8 @@ def test_do_not_prompt_for_authentication(
     server = make_mock_server(ssl_context=ctx)
 
     server.mock.side_effect = [
-        package_page(
-            {
-                "simple-3.0.tar.gz": "/files/simple-3.0.tar.gz",
-            }
-        ),
-        authorization_response(str(data.packages / "simple-3.0.tar.gz")),
+        package_page({"simple-3.0.tar.gz": "/files/simple-3.0.tar.gz"}),
+        authorization_response(data.packages / "simple-3.0.tar.gz"),
     ]
 
     url = f"https://{server.host}:{server.port}/simple"
@@ -372,13 +364,9 @@ def test_prompt_for_keyring_if_needed(
 
     server = make_mock_server(ssl_context=ctx)
     server.mock.side_effect = [
-        package_page(
-            {
-                "simple-3.0.tar.gz": "/files/simple-3.0.tar.gz",
-            }
-        ),
-        response(str(data.packages / "simple-3.0.tar.gz")),
-        response(str(data.packages / "simple-3.0.tar.gz")),
+        package_page({"simple-3.0.tar.gz": "/files/simple-3.0.tar.gz"}),
+        response(data.packages / "simple-3.0.tar.gz"),
+        response(data.packages / "simple-3.0.tar.gz"),
     ]
 
     url = f"https://{server.host}:{server.port}/simple"
diff --git a/tests/functional/test_install_direct_url.py b/tests/functional/test_install_direct_url.py
index 9d5e0612ea9..1749917cf5a 100644
--- a/tests/functional/test_install_direct_url.py
+++ b/tests/functional/test_install_direct_url.py
@@ -1,7 +1,7 @@
 import pytest
 
 from pip._internal.models.direct_url import VcsInfo
-from tests.lib import PipTestEnvironment, TestData, _create_test_package, path_to_url
+from tests.lib import PipTestEnvironment, TestData, _create_test_package
 from tests.lib.direct_url import get_created_direct_url
 
 
@@ -14,8 +14,7 @@ def test_install_find_links_no_direct_url(script: PipTestEnvironment) -> None:
 @pytest.mark.usefixtures("with_wheel")
 def test_install_vcs_editable_no_direct_url(script: PipTestEnvironment) -> None:
     pkg_path = _create_test_package(script, name="testpkg")
-    args = ["install", "-e", "git+%s#egg=testpkg" % path_to_url(pkg_path)]
-    result = script.pip(*args)
+    result = script.pip("install", "-e", f"git+{pkg_path.as_uri()}#egg=testpkg")
     # legacy editable installs do not generate .dist-info,
     # hence no direct_url.json
     assert not get_created_direct_url(result, "testpkg")
@@ -24,9 +23,8 @@ def test_install_vcs_editable_no_direct_url(script: PipTestEnvironment) -> None:
 @pytest.mark.usefixtures("with_wheel")
 def test_install_vcs_non_editable_direct_url(script: PipTestEnvironment) -> None:
     pkg_path = _create_test_package(script, name="testpkg")
-    url = path_to_url(pkg_path)
-    args = ["install", f"git+{url}#egg=testpkg"]
-    result = script.pip(*args)
+    url = pkg_path.as_uri()
+    result = script.pip("install", f"git+{url}#egg=testpkg")
     direct_url = get_created_direct_url(result, "testpkg")
     assert direct_url
     assert direct_url.url == url
@@ -36,9 +34,8 @@ def test_install_vcs_non_editable_direct_url(script: PipTestEnvironment) -> None
 
 @pytest.mark.usefixtures("with_wheel")
 def test_install_archive_direct_url(script: PipTestEnvironment, data: TestData) -> None:
-    req = "simple @ " + path_to_url(data.packages / "simple-2.0.tar.gz")
-    assert req.startswith("simple @ file://")
-    result = script.pip("install", req)
+    pkg_path = data.packages.joinpath("simple-2.0.tar.gz")
+    result = script.pip("install", f"simple @ {pkg_path.as_uri()}")
     assert get_created_direct_url(result, "simple")
 
 
@@ -58,8 +55,7 @@ def test_install_vcs_constraint_direct_url(script: PipTestEnvironment) -> None:
 @pytest.mark.usefixtures("with_wheel")
 def test_install_vcs_constraint_direct_file_url(script: PipTestEnvironment) -> None:
     pkg_path = _create_test_package(script, name="testpkg")
-    url = path_to_url(pkg_path)
     constraints_file = script.scratch_path / "constraints.txt"
-    constraints_file.write_text(f"git+{url}#egg=testpkg")
+    constraints_file.write_text(f"git+{pkg_path.as_uri()}#egg=testpkg")
     result = script.pip("install", "testpkg", "-c", constraints_file)
     assert get_created_direct_url(result, "testpkg")
diff --git a/tests/functional/test_install_extras.py b/tests/functional/test_install_extras.py
index c6cef00fa9c..de912545041 100644
--- a/tests/functional/test_install_extras.py
+++ b/tests/functional/test_install_extras.py
@@ -79,7 +79,7 @@ def test_nonexistent_extra_warns_user_no_wheel(
         "install",
         "--no-binary=:all:",
         "--no-index",
-        "--find-links=" + data.find_links,
+        f"--find-links={data.find_links}",
         "simple[nonexistent]",
         expect_stderr=True,
     )
@@ -100,7 +100,7 @@ def test_nonexistent_extra_warns_user_with_wheel(
     result = script.pip(
         "install",
         "--no-index",
-        "--find-links=" + data.find_links,
+        f"--find-links={data.find_links}",
         "simplewheel[nonexistent]",
         expect_stderr=True,
     )
@@ -116,7 +116,7 @@ def test_nonexistent_options_listed_in_order(
     result = script.pip(
         "install",
         "--no-index",
-        "--find-links=" + data.find_links,
+        f"--find-links={data.find_links}",
         "simplewheel[nonexistent, nope]",
         expect_stderr=True,
     )
@@ -142,7 +142,7 @@ def test_install_fails_if_extra_at_end(
     result = script.pip(
         "install",
         "--no-index",
-        "--find-links=" + data.find_links,
+        f"--find-links={data.find_links}",
         "-r",
         script.scratch_path / "requirements.txt",
         expect_error=True,
diff --git a/tests/functional/test_install_index.py b/tests/functional/test_install_index.py
index a492863b542..6c3c901a443 100644
--- a/tests/functional/test_install_index.py
+++ b/tests/functional/test_install_index.py
@@ -1,4 +1,3 @@
-import os
 import shutil
 import textwrap
 import urllib.parse
@@ -47,13 +46,11 @@ def test_find_links_requirements_file_relative_path(
     """Test find-links as a relative path to a reqs file."""
     script.scratch_path.joinpath("test-req.txt").write_text(
         textwrap.dedent(
-            """
+            f"""
         --no-index
-        --find-links={}
+        --find-links={data.packages.as_posix()}
         parent==0.1
-        """.format(
-                data.packages.replace(os.path.sep, "/")
-            )
+        """
         )
     )
     result = script.pip(
diff --git a/tests/functional/test_install_reqs.py b/tests/functional/test_install_reqs.py
index a7f2f46be94..1bce55141ad 100644
--- a/tests/functional/test_install_reqs.py
+++ b/tests/functional/test_install_reqs.py
@@ -1,5 +1,6 @@
 import json
 import os
+import pathlib
 import textwrap
 from typing import Any, Callable
 
@@ -13,15 +14,13 @@
     create_basic_sdist_for_package,
     create_basic_wheel_for_package,
     need_svn,
-    path_to_url,
     requirements_file,
 )
 from tests.lib.local_repos import local_checkout
-from tests.lib.path import Path
 
 
 class ArgRecordingSdist:
-    def __init__(self, sdist_path: Path, args_path: Path) -> None:
+    def __init__(self, sdist_path: pathlib.Path, args_path: pathlib.Path) -> None:
         self.sdist_path = sdist_path
         self._args_path = args_path
 
@@ -100,7 +99,12 @@ def test_schema_check_in_requirements_file(script: PipTestEnvironment) -> None:
     )
 
     with pytest.raises(AssertionError):
-        script.pip("install", "-vvv", "-r", script.scratch_path / "file-egg-req.txt")
+        script.pip(
+            "install",
+            "-vvv",
+            "-r",
+            script.scratch_path / "file-egg-req.txt",
+        )
 
 
 @pytest.mark.parametrize(
@@ -128,19 +132,16 @@ def test_relative_requirements_file(
     package_folder = script.site_packages / "fspkg"
 
     # Compute relative install path to FSPkg from scratch path.
-    full_rel_path = os.path.relpath(
-        data.packages.joinpath("FSPkg"), script.scratch_path
-    )
-    full_rel_url = "file:" + full_rel_path + "#egg=FSPkg"
+    full_rel_path = data.packages.joinpath("FSPkg").relative_to(script.scratch_path)
+    full_rel_url = f"{full_rel_path.as_uri()}#egg=FSPkg"
     embedded_rel_path = script.scratch_path.joinpath(full_rel_path)
 
     req_path = {
-        "rel_path": full_rel_path,
+        "rel_path": full_rel_path.as_posix(),
         "rel_url": full_rel_url,
-        "embedded_rel_path": embedded_rel_path,
+        "embedded_rel_path": embedded_rel_path.as_posix(),
     }[test_type]
 
-    req_path = req_path.replace(os.path.sep, "/")
     # Install as either editable or not.
     if not editable:
         with requirements_file(req_path + "\n", script.scratch_path) as reqs_file:
@@ -163,7 +164,10 @@ def test_relative_requirements_file(
 @pytest.mark.network
 @need_svn
 @pytest.mark.usefixtures("with_wheel")
-def test_multiple_requirements_files(script: PipTestEnvironment, tmpdir: Path) -> None:
+def test_multiple_requirements_files(
+    script: PipTestEnvironment,
+    tmp_path: pathlib.Path,
+) -> None:
     """
     Test installing from multiple nested requirements files.
 
@@ -176,7 +180,7 @@ def test_multiple_requirements_files(script: PipTestEnvironment, tmpdir: Path) -
             -r {}-req.txt
         """
         ).format(
-            local_checkout("svn+http://svn.colorstudy.com/INITools", tmpdir),
+            local_checkout("svn+http://svn.colorstudy.com/INITools", tmp_path),
             other_lib_name,
         ),
     )
@@ -264,7 +268,9 @@ def test_install_local_editable_with_extras(
 ) -> None:
     to_install = data.packages.joinpath("LocalExtras")
     res = script.pip_install_local(
-        "-e", to_install + "[bar]", allow_stderr_warning=True
+        "-e",
+        f"{to_install}[bar]",
+        allow_stderr_warning=True,
     )
     res.did_update(script.site_packages / "easy-install.pth")
     res.did_create(script.site_packages / "LocalExtras.egg-link")
@@ -281,13 +287,11 @@ def test_install_collected_dependencies_first(script: PipTestEnvironment) -> Non
 
 @pytest.mark.network
 def test_install_local_editable_with_subdirectory(script: PipTestEnvironment) -> None:
-    version_pkg_path = _create_test_package_with_subdirectory(script, "version_subdir")
+    uri = _create_test_package_with_subdirectory(script, "version_subdir").as_uri()
     result = script.pip(
         "install",
         "-e",
-        "{uri}#egg=version_subpkg&subdirectory=version_subdir".format(
-            uri="git+" + path_to_url(version_pkg_path),
-        ),
+        f"git+{uri}#egg=version_subpkg&subdirectory=version_subdir",
     )
 
     result.assert_installed("version-subpkg", sub_dir="version_subdir")
@@ -295,12 +299,10 @@ def test_install_local_editable_with_subdirectory(script: PipTestEnvironment) ->
 
 @pytest.mark.network
 def test_install_local_with_subdirectory(script: PipTestEnvironment) -> None:
-    version_pkg_path = _create_test_package_with_subdirectory(script, "version_subdir")
+    uri = _create_test_package_with_subdirectory(script, "version_subdir").as_uri()
     result = script.pip(
         "install",
-        "{uri}#egg=version_subpkg&subdirectory=version_subdir".format(
-            uri="git+" + path_to_url(version_pkg_path),
-        ),
+        f"git+{uri}#egg=version_subpkg&subdirectory=version_subdir",
     )
 
     result.assert_installed("version_subpkg.py", editable=False)
@@ -347,9 +349,9 @@ def test_install_option_in_requirements_file_overrides_cli(
         "install",
         "--no-index",
         "-f",
-        str(simple_sdist.sdist_path.parent),
+        simple_sdist.sdist_path.parent,
         "-r",
-        str(reqs_file),
+        reqs_file,
         "--install-option=-O1",
         allow_stderr_warning=True,
     )
@@ -456,7 +458,7 @@ def test_constraints_constrain_to_local_editable(
 ) -> None:
     to_install = data.src.joinpath("singlemodule")
     script.scratch_path.joinpath("constraints.txt").write_text(
-        "-e {url}#egg=singlemodule".format(url=path_to_url(to_install))
+        f"-e {to_install.as_uri()}#egg=singlemodule"
     )
     result = script.pip(
         "install",
@@ -480,7 +482,7 @@ def test_constraints_constrain_to_local(
 ) -> None:
     to_install = data.src.joinpath("singlemodule")
     script.scratch_path.joinpath("constraints.txt").write_text(
-        "{url}#egg=singlemodule".format(url=path_to_url(to_install))
+        f"{to_install.as_uri()}#egg=singlemodule"
     )
     result = script.pip(
         "install",
@@ -499,7 +501,7 @@ def test_constrained_to_url_install_same_url(
     script: PipTestEnvironment, data: TestData
 ) -> None:
     to_install = data.src.joinpath("singlemodule")
-    constraints = path_to_url(to_install) + "#egg=singlemodule"
+    constraints = f"{to_install.as_uri()}#egg=singlemodule"
     script.scratch_path.joinpath("constraints.txt").write_text(constraints)
     result = script.pip(
         "install",
@@ -516,7 +518,7 @@ def test_constrained_to_url_install_same_url(
 
 @pytest.mark.usefixtures("with_wheel")
 def test_double_install_spurious_hash_mismatch(
-    script: PipTestEnvironment, tmpdir: Path, data: TestData
+    script: PipTestEnvironment, tmp_path: pathlib.Path, data: TestData
 ) -> None:
     """Make sure installing the same hashed sdist twice doesn't throw hash
     mismatch errors.
@@ -531,7 +533,7 @@ def test_double_install_spurious_hash_mismatch(
     with requirements_file(
         "simple==1.0 --hash=sha256:393043e672415891885c9a2a"
         "0929b1af95fb866d6ca016b42d2e6ce53619b653",
-        tmpdir,
+        tmp_path,
     ) as reqs_file:
         # Install a package (and build its wheel):
         result = script.pip_install_local(
@@ -561,7 +563,7 @@ def test_install_with_extras_from_constraints(
 ) -> None:
     to_install = data.packages.joinpath("LocalExtras")
     script.scratch_path.joinpath("constraints.txt").write_text(
-        "{url}#egg=LocalExtras[bar]".format(url=path_to_url(to_install))
+        f"{to_install.as_uri()}#egg=LocalExtras[bar]"
     )
     result = script.pip_install_local(
         "-c",
@@ -599,7 +601,7 @@ def test_install_with_extras_joined(
 ) -> None:
     to_install = data.packages.joinpath("LocalExtras")
     script.scratch_path.joinpath("constraints.txt").write_text(
-        "{url}#egg=LocalExtras[bar]".format(url=path_to_url(to_install))
+        f"{to_install.as_uri()}#egg=LocalExtras[bar]"
     )
     result = script.pip_install_local(
         "-c",
@@ -620,7 +622,7 @@ def test_install_with_extras_editable_joined(
 ) -> None:
     to_install = data.packages.joinpath("LocalExtras")
     script.scratch_path.joinpath("constraints.txt").write_text(
-        "-e {url}#egg=LocalExtras[bar]".format(url=path_to_url(to_install))
+        f"-e {to_install.as_uri()}#egg=LocalExtras[bar]"
     )
     result = script.pip_install_local(
         "-c",
@@ -641,7 +643,7 @@ def test_install_distribution_full_union(
 ) -> None:
     to_install = data.packages.joinpath("LocalExtras")
     result = script.pip_install_local(
-        to_install, to_install + "[bar]", to_install + "[baz]"
+        to_install, f"{to_install}[bar]", f"{to_install}[baz]"
     )
     assert "Running setup.py install for LocalExtras" in result.stdout
     result.did_create(script.site_packages / "simple")
@@ -652,7 +654,7 @@ def test_install_distribution_duplicate_extras(
     script: PipTestEnvironment, data: TestData
 ) -> None:
     to_install = data.packages.joinpath("LocalExtras")
-    package_name = to_install + "[bar]"
+    package_name = f"{to_install}[bar]"
     with pytest.raises(AssertionError):
         result = script.pip_install_local(package_name, package_name)
         expected = f"Double requirement given: {package_name}"
@@ -669,7 +671,7 @@ def test_install_distribution_union_with_constraints(
     result = script.pip_install_local(
         "-c",
         script.scratch_path / "constraints.txt",
-        to_install + "[baz]",
+        f"{to_install}[baz]",
         allow_stderr_warning=True,
         expect_error=(resolver_variant == "2020-resolver"),
     )
@@ -689,8 +691,8 @@ def test_install_distribution_union_with_versions(
     to_install_001 = data.packages.joinpath("LocalExtras")
     to_install_002 = data.packages.joinpath("LocalExtras-0.0.2")
     result = script.pip_install_local(
-        to_install_001 + "[bar]",
-        to_install_002 + "[baz]",
+        f"{to_install_001}[bar]",
+        f"{to_install_002}[baz]",
         expect_error=(resolver_variant == "2020-resolver"),
     )
     if resolver_variant == "2020-resolver":
@@ -713,7 +715,7 @@ def test_install_distribution_union_conflicting_extras(
     # detected.
     to_install = data.packages.joinpath("LocalExtras-0.0.2")
     result = script.pip_install_local(
-        to_install, to_install + "[bar]", expect_error=True
+        to_install, f"{to_install}[bar]", expect_error=True
     )
     assert "installed" not in result.stdout
     assert "Conflict" in result.stderr
@@ -745,7 +747,7 @@ def test_install_unsupported_wheel_file(
     # Trying to install a local wheel with an incompatible version/type
     # should fail.
     path = data.packages.joinpath("simple.dist-0.1-py1-none-invalid.whl")
-    script.scratch_path.joinpath("wheel-file.txt").write_text(path + "\n")
+    script.scratch_path.joinpath("wheel-file.txt").write_text(f"{path}\n")
     result = script.pip(
         "install",
         "-r",
@@ -788,7 +790,7 @@ def test_install_options_local_to_package(
         "install",
         "--no-index",
         "-f",
-        str(simple1_sdist.sdist_path.parent),
+        simple1_sdist.sdist_path.parent,
         "-r",
         reqs_file,
         allow_stderr_warning=True,
@@ -810,7 +812,7 @@ def test_location_related_install_option_fails(script: PipTestEnvironment) -> No
         "install",
         "--no-index",
         "-f",
-        str(simple_sdist.parent),
+        simple_sdist.parent,
         "-r",
         reqs_file,
         expect_error=True,
diff --git a/tests/functional/test_install_upgrade.py b/tests/functional/test_install_upgrade.py
index 3dab9161e80..73f9ebcf850 100644
--- a/tests/functional/test_install_upgrade.py
+++ b/tests/functional/test_install_upgrade.py
@@ -1,5 +1,6 @@
 import itertools
 import os
+import pathlib
 import sys
 import textwrap
 
@@ -8,7 +9,6 @@
 from tests.lib import pyversion  # noqa: F401
 from tests.lib import PipTestEnvironment, ResolverVariant, TestData, assert_all_changes
 from tests.lib.local_repos import local_checkout
-from tests.lib.path import Path
 from tests.lib.wheel import make_wheel
 
 
@@ -262,7 +262,11 @@ def test_upgrade_from_reqs_file(script: PipTestEnvironment) -> None:
         """
         )
     )
-    install_result = script.pip("install", "-r", script.scratch_path / "test-req.txt")
+    install_result = script.pip(
+        "install",
+        "-r",
+        str(script.scratch_path / "test-req.txt"),
+    )
     script.scratch_path.joinpath("test-req.txt").write_text(
         textwrap.dedent(
             """\
@@ -272,7 +276,7 @@ def test_upgrade_from_reqs_file(script: PipTestEnvironment) -> None:
         """
         )
     )
-    script.pip("install", "--upgrade", "-r", script.scratch_path / "test-req.txt")
+    script.pip("install", "--upgrade", "-r", str(script.scratch_path / "test-req.txt"))
     uninstall_result = script.pip(
         "uninstall", "-r", script.scratch_path / "test-req.txt", "-y"
     )
@@ -341,13 +345,14 @@ def test_install_with_ignoreinstalled_requested(script: PipTestEnvironment) -> N
 
 @pytest.mark.network
 def test_upgrade_vcs_req_with_no_dists_found(
-    script: PipTestEnvironment, tmpdir: Path
+    script: PipTestEnvironment,
+    tmp_path: pathlib.Path,
 ) -> None:
     """It can upgrade a VCS requirement that has no distributions otherwise."""
     req = "{checkout}#egg=pip-test-package".format(
         checkout=local_checkout(
             "git+https://github.com/pypa/pip-test-package.git",
-            tmpdir,
+            tmp_path,
         )
     )
     script.pip("install", req)
diff --git a/tests/functional/test_install_user.py b/tests/functional/test_install_user.py
index 8657bc3ef2f..1d33bf52da5 100644
--- a/tests/functional/test_install_user.py
+++ b/tests/functional/test_install_user.py
@@ -1,6 +1,7 @@
 """
 tests specific to "pip install --user"
 """
+import pathlib
 import textwrap
 from os.path import curdir, isdir, isfile
 
@@ -9,7 +10,6 @@
 from tests.lib import pyversion  # noqa: F401
 from tests.lib import PipTestEnvironment, TestData, need_svn
 from tests.lib.local_repos import local_checkout
-from tests.lib.path import Path
 from tests.lib.venv import VirtualEnvironment
 
 
@@ -53,21 +53,20 @@ def test_reset_env_system_site_packages_usersite(
     @need_svn
     @pytest.mark.incompatible_with_test_venv
     def test_install_subversion_usersite_editable_with_distribute(
-        self, script: PipTestEnvironment, tmpdir: Path
+        self,
+        script: PipTestEnvironment,
+        tmp_path: pathlib.Path,
     ) -> None:
         """
         Test installing current directory ('.') into usersite after installing
         distribute
         """
+        checkout = local_checkout("svn+http://svn.colorstudy.com/INITools", tmp_path)
         result = script.pip(
             "install",
             "--user",
             "-e",
-            "{checkout}#egg=initools".format(
-                checkout=local_checkout(
-                    "svn+http://svn.colorstudy.com/INITools", tmpdir
-                )
-            ),
+            f"{checkout}#egg=initools",
         )
         result.assert_installed("INITools", use_user_site=True)
 
diff --git a/tests/functional/test_install_vcs_git.py b/tests/functional/test_install_vcs_git.py
index 04413c86d4b..cb5bd5e2b35 100644
--- a/tests/functional/test_install_vcs_git.py
+++ b/tests/functional/test_install_vcs_git.py
@@ -1,25 +1,26 @@
+import pathlib
 from typing import Optional
 
 import pytest
 
-from pip._internal.utils.urls import path_to_url
 from tests.lib import pyversion  # noqa: F401
 from tests.lib import (
     PipTestEnvironment,
     _change_test_package_version,
     _create_test_package,
-    _test_path_to_file_url,
 )
 from tests.lib.git_submodule_helpers import (
-    _change_test_package_submodule,
-    _create_test_package_with_submodule,
-    _pull_in_submodule_changes_to_module,
+    change_test_package_submodule,
+    create_test_package_with_submodule,
+    pull_in_submodule_changes_to_module,
 )
 from tests.lib.local_repos import local_checkout
-from tests.lib.path import Path
 
 
-def _get_editable_repo_dir(script: PipTestEnvironment, package_name: str) -> Path:
+def _get_editable_repo_dir(
+    script: PipTestEnvironment,
+    package_name: str,
+) -> pathlib.Path:
     """
     Return the repository directory for an editable install.
     """
@@ -46,7 +47,7 @@ def _get_branch_remote(
 
 def _github_checkout(
     url_path: str,
-    temp_dir: Path,
+    temp_path: pathlib.Path,
     rev: Optional[str] = None,
     egg: Optional[str] = None,
     scheme: Optional[str] = None,
@@ -65,7 +66,7 @@ def _github_checkout(
     if scheme is None:
         scheme = "https"
     url = f"git+{scheme}://github.com/{url_path}"
-    local_url = local_checkout(url, temp_dir)
+    local_url = local_checkout(url, temp_path)
     if rev is not None:
         local_url += f"@{rev}"
     if egg is not None:
@@ -75,7 +76,7 @@ def _github_checkout(
 
 
 def _make_version_pkg_url(
-    path: Path, rev: Optional[str] = None, name: str = "version_pkg"
+    path: pathlib.Path, rev: Optional[str] = None, name: str = "version_pkg"
 ) -> str:
     """
     Return a "git+file://" URL to the version_pkg test package.
@@ -85,16 +86,13 @@ def _make_version_pkg_url(
         containing the version_pkg package.
       rev: an optional revision to install like a branch name, tag, or SHA.
     """
-    file_url = _test_path_to_file_url(path)
     url_rev = "" if rev is None else f"@{rev}"
-    url = f"git+{file_url}{url_rev}#egg={name}"
-
-    return url
+    return f"git+{path.as_uri()}{url_rev}#egg={name}"
 
 
 def _install_version_pkg_only(
     script: PipTestEnvironment,
-    path: Path,
+    path: pathlib.Path,
     rev: Optional[str] = None,
     expect_stderr: bool = False,
 ) -> None:
@@ -113,7 +111,7 @@ def _install_version_pkg_only(
 
 def _install_version_pkg(
     script: PipTestEnvironment,
-    path: Path,
+    path: pathlib.Path,
     rev: Optional[str] = None,
     expect_stderr: bool = False,
 ) -> str:
@@ -174,13 +172,13 @@ def test_git_install_branch_again_after_branch_changes(
 
 @pytest.mark.network
 def test_install_editable_from_git_with_https(
-    script: PipTestEnvironment, tmpdir: Path
+    script: PipTestEnvironment, tmp_path: pathlib.Path
 ) -> None:
     """
     Test cloning from Git with https.
     """
     url_path = "pypa/pip-test-package.git"
-    local_url = _github_checkout(url_path, tmpdir, egg="pip-test-package")
+    local_url = _github_checkout(url_path, tmp_path, egg="pip-test-package")
     result = script.pip("install", "-e", local_url)
     result.assert_installed("pip-test-package", with_files=[".git"])
 
@@ -256,7 +254,7 @@ def test_git_with_tag_name_as_revision(script: PipTestEnvironment) -> None:
     assert "0.1" == version
 
 
-def _add_ref(script: PipTestEnvironment, path: Path, ref: str) -> None:
+def _add_ref(script: PipTestEnvironment, path: pathlib.Path, ref: str) -> None:
     """
     Add a new ref to a repository at the given path.
     """
@@ -316,13 +314,16 @@ def test_git_install_then_install_ref(script: PipTestEnvironment) -> None:
     ],
 )
 def test_install_git_logs_commit_sha(
-    script: PipTestEnvironment, rev: str, expected_sha: str, tmpdir: Path
+    script: PipTestEnvironment,
+    rev: str,
+    expected_sha: str,
+    tmp_path: pathlib.Path,
 ) -> None:
     """
     Test installing from a git repository logs a commit SHA.
     """
     url_path = "pypa/pip-test-package.git"
-    base_local_url = _github_checkout(url_path, tmpdir)
+    base_local_url = _github_checkout(url_path, tmp_path)
     local_url = f"{base_local_url}{rev}#egg=pip-test-package"
     result = script.pip("install", local_url)
     # `[4:]` removes a 'git+' prefix
@@ -330,12 +331,15 @@ def test_install_git_logs_commit_sha(
 
 
 @pytest.mark.network
-def test_git_with_tag_name_and_update(script: PipTestEnvironment, tmpdir: Path) -> None:
+def test_git_with_tag_name_and_update(
+    script: PipTestEnvironment,
+    tmp_path: pathlib.Path,
+) -> None:
     """
     Test cloning a git repository and updating to a different version.
     """
     url_path = "pypa/pip-test-package.git"
-    base_local_url = _github_checkout(url_path, tmpdir)
+    base_local_url = _github_checkout(url_path, tmp_path)
 
     local_url = f"{base_local_url}#egg=pip-test-package"
     result = script.pip("install", "-e", local_url)
@@ -354,14 +358,14 @@ def test_git_with_tag_name_and_update(script: PipTestEnvironment, tmpdir: Path)
 
 @pytest.mark.network
 def test_git_branch_should_not_be_changed(
-    script: PipTestEnvironment, tmpdir: Path
+    script: PipTestEnvironment, tmp_path: pathlib.Path
 ) -> None:
     """
     Editable installations should not change branch
     related to issue #32 and #161
     """
     url_path = "pypa/pip-test-package.git"
-    local_url = _github_checkout(url_path, tmpdir, egg="pip-test-package")
+    local_url = _github_checkout(url_path, tmp_path, egg="pip-test-package")
     script.pip("install", "-e", local_url)
     branch = _get_editable_branch(script, "pip-test-package")
     assert "master" == branch
@@ -369,7 +373,7 @@ def test_git_branch_should_not_be_changed(
 
 @pytest.mark.network
 def test_git_with_non_editable_unpacking(
-    script: PipTestEnvironment, tmpdir: Path
+    script: PipTestEnvironment, tmp_path: pathlib.Path
 ) -> None:
     """
     Test cloning a git repository from a non-editable URL with a given tag.
@@ -377,7 +381,7 @@ def test_git_with_non_editable_unpacking(
     url_path = "pypa/pip-test-package.git"
     local_url = _github_checkout(
         url_path,
-        tmpdir,
+        tmp_path,
         rev="0.1.2",
         egg="pip-test-package",
     )
@@ -392,7 +396,7 @@ def test_git_with_non_editable_unpacking(
 
 @pytest.mark.network
 def test_git_with_editable_where_egg_contains_dev_string(
-    script: PipTestEnvironment, tmpdir: Path
+    script: PipTestEnvironment, tmp_path: pathlib.Path
 ) -> None:
     """
     Test cloning a git repository from an editable url which contains "dev"
@@ -401,7 +405,7 @@ def test_git_with_editable_where_egg_contains_dev_string(
     url_path = "dcramer/django-devserver.git"
     local_url = _github_checkout(
         url_path,
-        tmpdir,
+        tmp_path,
         egg="django-devserver",
         scheme="https",
     )
@@ -411,7 +415,7 @@ def test_git_with_editable_where_egg_contains_dev_string(
 
 @pytest.mark.network
 def test_git_with_non_editable_where_egg_contains_dev_string(
-    script: PipTestEnvironment, tmpdir: Path
+    script: PipTestEnvironment, tmp_path: pathlib.Path
 ) -> None:
     """
     Test cloning a git repository from a non-editable url which contains "dev"
@@ -420,7 +424,7 @@ def test_git_with_non_editable_where_egg_contains_dev_string(
     url_path = "dcramer/django-devserver.git"
     local_url = _github_checkout(
         url_path,
-        tmpdir,
+        tmp_path,
         egg="django-devserver",
         scheme="https",
     )
@@ -538,17 +542,17 @@ def test_check_submodule_addition(script: PipTestEnvironment) -> None:
     """
     Submodules are pulled in on install and updated on upgrade.
     """
-    module_path, submodule_path = _create_test_package_with_submodule(
+    module_path, submodule_path = create_test_package_with_submodule(
         script, rel_path="testpkg/static"
     )
 
     install_result = script.pip(
-        "install", "-e", "git+" + path_to_url(module_path) + "#egg=version_pkg"
+        "install", "-e", f"git+{module_path.as_uri()}#egg=version_pkg"
     )
     install_result.did_create(script.venv / "src/version-pkg/testpkg/static/testfile")
 
-    _change_test_package_submodule(script, submodule_path)
-    _pull_in_submodule_changes_to_module(
+    change_test_package_submodule(script, submodule_path)
+    pull_in_submodule_changes_to_module(
         script,
         module_path,
         rel_path="testpkg/static",
@@ -558,7 +562,7 @@ def test_check_submodule_addition(script: PipTestEnvironment) -> None:
     update_result = script.pip(
         "install",
         "-e",
-        "git+" + path_to_url(module_path) + "#egg=version_pkg",
+        f"git+{module_path.as_uri()}#egg=version_pkg",
         "--upgrade",
     )
 
diff --git a/tests/functional/test_install_wheel.py b/tests/functional/test_install_wheel.py
index 86c5e5fbeb2..db89126e461 100644
--- a/tests/functional/test_install_wheel.py
+++ b/tests/functional/test_install_wheel.py
@@ -1,14 +1,13 @@
 import csv
 import distutils
-import glob
 import os
+import pathlib
 import shutil
 from typing import Any
 
 import pytest
 
 from tests.lib import PipTestEnvironment, TestData, create_basic_wheel_for_package
-from tests.lib.path import Path
 from tests.lib.wheel import WheelBuilder, make_wheel
 
 
@@ -20,7 +19,7 @@ def make_wheel_with_file(name: str, version: str, **kwargs: Any) -> WheelBuilder
 
 
 def test_install_from_future_wheel_version(
-    script: PipTestEnvironment, tmpdir: Path
+    script: PipTestEnvironment, tmp_path: pathlib.Path
 ) -> None:
     """
     Test installing a wheel with a WHEEL metadata version that is:
@@ -33,7 +32,7 @@ def test_install_from_future_wheel_version(
         name="futurewheel",
         version="3.0",
         wheel_metadata_updates={"Wheel-Version": "3.0"},
-    ).save_to_dir(tmpdir)
+    ).save_to_dir(tmp_path)
 
     result = script.pip("install", package, "--no-index", expect_error=True)
     with pytest.raises(TestFailure):
@@ -43,7 +42,7 @@ def test_install_from_future_wheel_version(
         name="futurewheel",
         version="1.9",
         wheel_metadata_updates={"Wheel-Version": "1.9"},
-    ).save_to_dir(tmpdir)
+    ).save_to_dir(tmp_path)
     result = script.pip("install", package, "--no-index", expect_stderr=True)
     result.assert_installed("futurewheel", without_egg_link=True, editable=False)
 
@@ -70,18 +69,18 @@ def test_install_from_broken_wheel(
 
 
 def test_basic_install_from_wheel(
-    script: PipTestEnvironment, shared_data: TestData, tmpdir: Path
+    script: PipTestEnvironment, shared_data: TestData, tmp_path: pathlib.Path
 ) -> None:
     """
     Test installing from a wheel (that has a script)
     """
-    shutil.copy(shared_data.packages / "has.script-1.0-py2.py3-none-any.whl", tmpdir)
+    shutil.copy(shared_data.packages / "has.script-1.0-py2.py3-none-any.whl", tmp_path)
     result = script.pip(
         "install",
         "has.script==1.0",
         "--no-index",
         "--find-links",
-        tmpdir,
+        tmp_path,
     )
     dist_info_folder = script.site_packages / "has.script-1.0.dist-info"
     result.did_create(dist_info_folder)
@@ -90,19 +89,22 @@ def test_basic_install_from_wheel(
 
 
 def test_basic_install_from_wheel_with_extras(
-    script: PipTestEnvironment, shared_data: TestData, tmpdir: Path
+    script: PipTestEnvironment, shared_data: TestData, tmp_path: pathlib.Path
 ) -> None:
     """
     Test installing from a wheel with extras.
     """
-    shutil.copy(shared_data.packages / "complex_dist-0.1-py2.py3-none-any.whl", tmpdir)
-    shutil.copy(shared_data.packages / "simple.dist-0.1-py2.py3-none-any.whl", tmpdir)
+    shutil.copy(
+        shared_data.packages / "complex_dist-0.1-py2.py3-none-any.whl",
+        tmp_path,
+    )
+    shutil.copy(shared_data.packages / "simple.dist-0.1-py2.py3-none-any.whl", tmp_path)
     result = script.pip(
         "install",
         "complex-dist[simple]",
         "--no-index",
         "--find-links",
-        tmpdir,
+        tmp_path,
     )
     dist_info_folder = script.site_packages / "complex_dist-0.1.dist-info"
     result.did_create(dist_info_folder)
@@ -165,14 +167,14 @@ def test_basic_install_from_unicode_wheel(
 
 def get_header_scheme_path_for_script(
     script: PipTestEnvironment, dist_name: str
-) -> Path:
+) -> pathlib.Path:
     command = (
-        "from pip._internal.locations import get_scheme;"
-        "scheme = get_scheme({!r});"
-        "print(scheme.headers);"
-    ).format(dist_name)
+        f"from pip._internal.locations import get_scheme;"
+        f"scheme = get_scheme({dist_name!r});"
+        f"print(scheme.headers);"
+    )
     result = script.run("python", "-c", command).stdout
-    return Path(result.strip())
+    return pathlib.Path(result.strip())
 
 
 def test_install_from_wheel_with_headers(script: PipTestEnvironment) -> None:
@@ -196,12 +198,12 @@ def test_install_from_wheel_with_headers(script: PipTestEnvironment) -> None:
 
 @pytest.mark.usefixtures("with_wheel")
 def test_install_wheel_with_target(
-    script: PipTestEnvironment, shared_data: TestData, tmpdir: Path
+    script: PipTestEnvironment, shared_data: TestData, tmp_path: pathlib.Path
 ) -> None:
     """
     Test installing a wheel using pip install --target
     """
-    shutil.copy(shared_data.packages / "simple.dist-0.1-py2.py3-none-any.whl", tmpdir)
+    shutil.copy(shared_data.packages / "simple.dist-0.1-py2.py3-none-any.whl", tmp_path)
     target_dir = script.scratch_path / "target"
     result = script.pip(
         "install",
@@ -210,9 +212,9 @@ def test_install_wheel_with_target(
         target_dir,
         "--no-index",
         "--find-links",
-        tmpdir,
+        tmp_path,
     )
-    result.did_create(Path("scratch") / "target" / "simpledist")
+    result.did_create("scratch/target/simpledist")
 
 
 @pytest.mark.usefixtures("with_wheel")
@@ -240,20 +242,20 @@ def test_install_wheel_with_target_and_data_files(
     target_dir = script.scratch_path / "prjwithdatafile"
     package = data.packages.joinpath("prjwithdatafile-1.0-py2.py3-none-any.whl")
     result = script.pip("install", package, "-t", target_dir, "--no-index")
-    project_path = Path("scratch") / "prjwithdatafile"
+    project_path = pathlib.Path("scratch", "prjwithdatafile")
     result.did_create(project_path / "packages1" / "README.txt")
     result.did_create(project_path / "packages2" / "README.txt")
     result.did_not_create(project_path / "lib" / "python")
 
 
 def test_install_wheel_with_root(
-    script: PipTestEnvironment, shared_data: TestData, tmpdir: Path
+    script: PipTestEnvironment, shared_data: TestData, tmp_path: pathlib.Path
 ) -> None:
     """
     Test installing a wheel using pip install --root
     """
     root_dir = script.scratch_path / "root"
-    shutil.copy(shared_data.packages / "simple.dist-0.1-py2.py3-none-any.whl", tmpdir)
+    shutil.copy(shared_data.packages / "simple.dist-0.1-py2.py3-none-any.whl", tmp_path)
     result = script.pip(
         "install",
         "simple.dist==0.1",
@@ -261,19 +263,19 @@ def test_install_wheel_with_root(
         root_dir,
         "--no-index",
         "--find-links",
-        tmpdir,
+        tmp_path,
     )
-    result.did_create(Path("scratch") / "root")
+    result.did_create("scratch/root")
 
 
 def test_install_wheel_with_prefix(
-    script: PipTestEnvironment, shared_data: TestData, tmpdir: Path
+    script: PipTestEnvironment, shared_data: TestData, tmp_path: pathlib.Path
 ) -> None:
     """
     Test installing a wheel using pip install --prefix
     """
     prefix_dir = script.scratch_path / "prefix"
-    shutil.copy(shared_data.packages / "simple.dist-0.1-py2.py3-none-any.whl", tmpdir)
+    shutil.copy(shared_data.packages / "simple.dist-0.1-py2.py3-none-any.whl", tmp_path)
     result = script.pip(
         "install",
         "simple.dist==0.1",
@@ -281,45 +283,45 @@ def test_install_wheel_with_prefix(
         prefix_dir,
         "--no-index",
         "--find-links",
-        tmpdir,
+        tmp_path,
     )
-    lib = distutils.sysconfig.get_python_lib(prefix=Path("scratch") / "prefix")
+    lib = distutils.sysconfig.get_python_lib(prefix="scratch/prefix")
     result.did_create(lib)
 
 
 def test_install_from_wheel_installs_deps(
-    script: PipTestEnvironment, data: TestData, tmpdir: Path
+    script: PipTestEnvironment, data: TestData, tmp_path: pathlib.Path
 ) -> None:
     """
     Test can install dependencies of wheels
     """
     # 'requires_source' depends on the 'source' project
     package = data.packages.joinpath("requires_source-1.0-py2.py3-none-any.whl")
-    shutil.copy(data.packages / "source-1.0.tar.gz", tmpdir)
+    shutil.copy(data.packages / "source-1.0.tar.gz", tmp_path)
     result = script.pip(
         "install",
         "--no-index",
         "--find-links",
-        tmpdir,
+        tmp_path,
         package,
     )
     result.assert_installed("source", editable=False)
 
 
 def test_install_from_wheel_no_deps(
-    script: PipTestEnvironment, data: TestData, tmpdir: Path
+    script: PipTestEnvironment, data: TestData, tmp_path: pathlib.Path
 ) -> None:
     """
     Test --no-deps works with wheel installs
     """
     # 'requires_source' depends on the 'source' project
     package = data.packages.joinpath("requires_source-1.0-py2.py3-none-any.whl")
-    shutil.copy(data.packages / "source-1.0.tar.gz", tmpdir)
+    shutil.copy(data.packages / "source-1.0.tar.gz", tmp_path)
     result = script.pip(
         "install",
         "--no-index",
         "--find-links",
-        tmpdir,
+        tmp_path,
         "--no-deps",
         package,
     )
@@ -340,7 +342,7 @@ def test_wheel_record_lines_in_deterministic_order(
     result.did_create(record_path)
 
     record_path = result.files_created[record_path].full
-    record_lines = [p for p in Path(record_path).read_text().split("\n") if p]
+    record_lines = [p for p in pathlib.Path(record_path).read_text().split("\n") if p]
     assert record_lines == sorted(record_lines)
 
 
@@ -368,19 +370,19 @@ def test_wheel_record_lines_have_hash_for_data_files(
 @pytest.mark.incompatible_with_test_venv
 @pytest.mark.usefixtures("with_wheel")
 def test_install_user_wheel(
-    script: PipTestEnvironment, shared_data: TestData, tmpdir: Path
+    script: PipTestEnvironment, shared_data: TestData, tmp_path: pathlib.Path
 ) -> None:
     """
     Test user install from wheel (that has a script)
     """
-    shutil.copy(shared_data.packages / "has.script-1.0-py2.py3-none-any.whl", tmpdir)
+    shutil.copy(shared_data.packages / "has.script-1.0-py2.py3-none-any.whl", tmp_path)
     result = script.pip(
         "install",
         "has.script==1.0",
         "--user",
         "--no-index",
         "--find-links",
-        tmpdir,
+        tmp_path,
     )
     dist_info_folder = script.user_site / "has.script-1.0.dist-info"
     result.did_create(dist_info_folder)
@@ -389,21 +391,21 @@ def test_install_user_wheel(
 
 
 def test_install_from_wheel_gen_entrypoint(
-    script: PipTestEnvironment, shared_data: TestData, tmpdir: Path
+    script: PipTestEnvironment, shared_data: TestData, tmp_path: pathlib.Path
 ) -> None:
     """
     Test installing scripts (entry points are generated)
     """
     shutil.copy(
         shared_data.packages / "script.wheel1a-0.1-py2.py3-none-any.whl",
-        tmpdir,
+        tmp_path,
     )
     result = script.pip(
         "install",
         "script.wheel1a==0.1",
         "--no-index",
         "--find-links",
-        tmpdir,
+        tmp_path,
     )
     if os.name == "nt":
         wrapper_file = script.bin / "t1.exe"
@@ -416,21 +418,21 @@ def test_install_from_wheel_gen_entrypoint(
 
 
 def test_install_from_wheel_gen_uppercase_entrypoint(
-    script: PipTestEnvironment, shared_data: TestData, tmpdir: Path
+    script: PipTestEnvironment, shared_data: TestData, tmp_path: pathlib.Path
 ) -> None:
     """
     Test installing scripts with uppercase letters in entry point names
     """
     shutil.copy(
         shared_data.packages / "console_scripts_uppercase-1.0-py2.py3-none-any.whl",
-        tmpdir,
+        tmp_path,
     )
     result = script.pip(
         "install",
         "console-scripts-uppercase==1.0",
         "--no-index",
         "--find-links",
-        tmpdir,
+        tmp_path,
     )
     if os.name == "nt":
         # Case probably doesn't make any difference on NT
@@ -464,21 +466,21 @@ def test_install_from_wheel_gen_unicode_entrypoint(script: PipTestEnvironment) -
 
 
 def test_install_from_wheel_with_legacy(
-    script: PipTestEnvironment, shared_data: TestData, tmpdir: Path
+    script: PipTestEnvironment, shared_data: TestData, tmp_path: pathlib.Path
 ) -> None:
     """
     Test installing scripts (legacy scripts are preserved)
     """
     shutil.copy(
         shared_data.packages / "script.wheel2a-0.1-py2.py3-none-any.whl",
-        tmpdir,
+        tmp_path,
     )
     result = script.pip(
         "install",
         "script.wheel2a==0.1",
         "--no-index",
         "--find-links",
-        tmpdir,
+        tmp_path,
     )
 
     legacy_file1 = script.bin / "testscript1.bat"
@@ -489,19 +491,22 @@ def test_install_from_wheel_with_legacy(
 
 
 def test_install_from_wheel_no_setuptools_entrypoint(
-    script: PipTestEnvironment, shared_data: TestData, tmpdir: Path
+    script: PipTestEnvironment, shared_data: TestData, tmp_path: pathlib.Path
 ) -> None:
     """
     Test that when we generate scripts, any existing setuptools wrappers in
     the wheel are skipped.
     """
-    shutil.copy(shared_data.packages / "script.wheel1-0.1-py2.py3-none-any.whl", tmpdir)
+    shutil.copy(
+        shared_data.packages / "script.wheel1-0.1-py2.py3-none-any.whl",
+        tmp_path,
+    )
     result = script.pip(
         "install",
         "script.wheel1==0.1",
         "--no-index",
         "--find-links",
-        tmpdir,
+        tmp_path,
     )
     if os.name == "nt":
         wrapper_file = script.bin / "t1.exe"
@@ -519,19 +524,22 @@ def test_install_from_wheel_no_setuptools_entrypoint(
 
 
 def test_skipping_setuptools_doesnt_skip_legacy(
-    script: PipTestEnvironment, shared_data: TestData, tmpdir: Path
+    script: PipTestEnvironment, shared_data: TestData, tmp_path: pathlib.Path
 ) -> None:
     """
     Test installing scripts (legacy scripts are preserved even when we skip
     setuptools wrappers)
     """
-    shutil.copy(shared_data.packages / "script.wheel2-0.1-py2.py3-none-any.whl", tmpdir)
+    shutil.copy(
+        shared_data.packages / "script.wheel2-0.1-py2.py3-none-any.whl",
+        tmp_path,
+    )
     result = script.pip(
         "install",
         "script.wheel2==0.1",
         "--no-index",
         "--find-links",
-        tmpdir,
+        tmp_path,
     )
 
     legacy_file1 = script.bin / "testscript1.bat"
@@ -544,18 +552,21 @@ def test_skipping_setuptools_doesnt_skip_legacy(
 
 
 def test_install_from_wheel_gui_entrypoint(
-    script: PipTestEnvironment, shared_data: TestData, tmpdir: Path
+    script: PipTestEnvironment, shared_data: TestData, tmp_path: pathlib.Path
 ) -> None:
     """
     Test installing scripts (gui entry points are generated)
     """
-    shutil.copy(shared_data.packages / "script.wheel3-0.1-py2.py3-none-any.whl", tmpdir)
+    shutil.copy(
+        shared_data.packages / "script.wheel3-0.1-py2.py3-none-any.whl",
+        tmp_path,
+    )
     result = script.pip(
         "install",
         "script.wheel3==0.1",
         "--no-index",
         "--find-links",
-        tmpdir,
+        tmp_path,
     )
     if os.name == "nt":
         wrapper_file = script.bin / "t1.exe"
@@ -565,49 +576,49 @@ def test_install_from_wheel_gui_entrypoint(
 
 
 def test_wheel_compiles_pyc(
-    script: PipTestEnvironment, shared_data: TestData, tmpdir: Path
+    script: PipTestEnvironment, shared_data: TestData, tmp_path: pathlib.Path
 ) -> None:
     """
     Test installing from wheel with --compile on
     """
-    shutil.copy(shared_data.packages / "simple.dist-0.1-py2.py3-none-any.whl", tmpdir)
+    shutil.copy(shared_data.packages / "simple.dist-0.1-py2.py3-none-any.whl", tmp_path)
     script.pip(
         "install",
         "--compile",
         "simple.dist==0.1",
         "--no-index",
         "--find-links",
-        tmpdir,
+        tmp_path,
     )
     # There are many locations for the __init__.pyc file so attempt to find
     #   any of them
     exists = [
         os.path.exists(script.site_packages_path / "simpledist/__init__.pyc"),
-        *glob.glob(script.site_packages_path / "simpledist/__pycache__/__init__*.pyc"),
+        *script.site_packages_path.glob("simpledist/__pycache__/__init__*.pyc"),
     ]
     assert any(exists)
 
 
 def test_wheel_no_compiles_pyc(
-    script: PipTestEnvironment, shared_data: TestData, tmpdir: Path
+    script: PipTestEnvironment, shared_data: TestData, tmp_path: pathlib.Path
 ) -> None:
     """
     Test installing from wheel with --compile on
     """
-    shutil.copy(shared_data.packages / "simple.dist-0.1-py2.py3-none-any.whl", tmpdir)
+    shutil.copy(shared_data.packages / "simple.dist-0.1-py2.py3-none-any.whl", tmp_path)
     script.pip(
         "install",
         "--no-compile",
         "simple.dist==0.1",
         "--no-index",
         "--find-links",
-        tmpdir,
+        tmp_path,
     )
     # There are many locations for the __init__.pyc file so attempt to find
     #   any of them
     exists = [
         os.path.exists(script.site_packages_path / "simpledist/__init__.pyc"),
-        *glob.glob(script.site_packages_path / "simpledist/__pycache__/__init__*.pyc"),
+        *script.site_packages_path.glob("simpledist/__pycache__/__init__*.pyc"),
     ]
 
     assert not any(exists)
@@ -739,7 +750,7 @@ def test_correct_package_name_while_creating_wheel_bug(
 
 @pytest.mark.parametrize("name", ["purelib", "abc"])
 def test_wheel_with_file_in_data_dir_has_reasonable_error(
-    script: PipTestEnvironment, tmpdir: Path, name: str
+    script: PipTestEnvironment, tmp_path: pathlib.Path, name: str
 ) -> None:
     """Normally we expect entities in the .data directory to be in a
     subdirectory, but if they are not then we should show a reasonable error
@@ -747,18 +758,18 @@ def test_wheel_with_file_in_data_dir_has_reasonable_error(
     """
     wheel_path = make_wheel(
         "simple", "0.1.0", extra_data_files={name: "hello world"}
-    ).save_to_dir(tmpdir)
+    ).save_to_dir(tmp_path)
 
-    result = script.pip("install", "--no-index", str(wheel_path), expect_error=True)
+    result = script.pip("install", "--no-index", wheel_path, expect_error=True)
     assert f"simple-0.1.0.data/{name}" in result.stderr
 
 
 def test_wheel_with_unknown_subdir_in_data_dir_has_reasonable_error(
-    script: PipTestEnvironment, tmpdir: Path
+    script: PipTestEnvironment, tmp_path: pathlib.Path
 ) -> None:
     wheel_path = make_wheel(
         "simple", "0.1.0", extra_data_files={"unknown/hello.txt": "hello world"}
-    ).save_to_dir(tmpdir)
+    ).save_to_dir(tmp_path)
 
-    result = script.pip("install", "--no-index", str(wheel_path), expect_error=True)
+    result = script.pip("install", "--no-index", wheel_path, expect_error=True)
     assert "simple-0.1.0.data/unknown/hello.txt" in result.stderr
diff --git a/tests/functional/test_list.py b/tests/functional/test_list.py
index b9d0f0fa340..66e98f07d2c 100644
--- a/tests/functional/test_list.py
+++ b/tests/functional/test_list.py
@@ -1,5 +1,6 @@
 import json
 import os
+import pathlib
 
 import pytest
 
@@ -13,17 +14,16 @@
     wheel,
 )
 from tests.lib.direct_url import get_created_direct_url_path
-from tests.lib.path import Path
 
 
 @pytest.fixture(scope="session")
 def simple_script(
-    tmpdir_factory: pytest.TempdirFactory,
+    tmp_path_factory: pytest.TempPathFactory,
     script_factory: ScriptFactory,
     shared_data: TestData,
 ) -> PipTestEnvironment:
-    tmpdir = Path(str(tmpdir_factory.mktemp("pip_test_package")))
-    script = script_factory(tmpdir.joinpath("workspace"))
+    tmp_path = tmp_path_factory.mktemp("pip_test_package")
+    script = script_factory(tmp_path.joinpath("workspace"))
     script.pip(
         "install",
         "-f",
@@ -113,10 +113,10 @@ def test_local_columns_flag(simple_script: PipTestEnvironment) -> None:
 
 
 def test_multiple_exclude_and_normalization(
-    script: PipTestEnvironment, tmpdir: Path
+    script: PipTestEnvironment, tmp_path: pathlib.Path
 ) -> None:
     req_path = wheel.make_wheel(name="Normalizable_Name", version="1.0").save_to_dir(
-        tmpdir
+        tmp_path
     )
     script.pip("install", "--no-index", req_path)
     result = script.pip("list")
@@ -336,11 +336,11 @@ def test_outdated_columns_flag(script: PipTestEnvironment, data: TestData) -> No
 
 @pytest.fixture(scope="session")
 def pip_test_package_script(
-    tmpdir_factory: pytest.TempdirFactory,
+    tmp_path_factory: pytest.TempPathFactory,
     script_factory: ScriptFactory,
     shared_data: TestData,
 ) -> PipTestEnvironment:
-    tmpdir = Path(str(tmpdir_factory.mktemp("pip_test_package")))
+    tmpdir = tmp_path_factory.mktemp("pip_test_package")
     script = script_factory(tmpdir.joinpath("workspace"))
     script.pip("install", "-f", shared_data.find_links, "--no-index", "simple==1.0")
     script.pip(
@@ -638,50 +638,51 @@ def test_list_json(simple_script: PipTestEnvironment) -> None:
     assert {"name": "simple2", "version": "3.0"} in data
 
 
-def test_list_path(tmpdir: Path, script: PipTestEnvironment, data: TestData) -> None:
+@pytest.mark.usefixtures("data")
+def test_list_path(tmp_path: pathlib.Path, script: PipTestEnvironment) -> None:
     """
     Test list with --path.
     """
-    result = script.pip("list", "--path", tmpdir, "--format=json")
+    result = script.pip("list", "--path", tmp_path, "--format=json")
     json_result = json.loads(result.stdout)
     assert {"name": "simple", "version": "2.0"} not in json_result
 
-    script.pip_install_local("--target", tmpdir, "simple==2.0")
-    result = script.pip("list", "--path", tmpdir, "--format=json")
+    script.pip_install_local("--target", tmp_path, "simple==2.0")
+    result = script.pip("list", "--path", tmp_path, "--format=json")
     json_result = json.loads(result.stdout)
     assert {"name": "simple", "version": "2.0"} in json_result
 
 
 @pytest.mark.incompatible_with_test_venv
 def test_list_path_exclude_user(
-    tmpdir: Path, script: PipTestEnvironment, data: TestData
+    tmp_path: pathlib.Path, script: PipTestEnvironment, data: TestData
 ) -> None:
     """
     Test list with --path and make sure packages from --user are not picked
     up.
     """
     script.pip_install_local("--user", "simple2")
-    script.pip_install_local("--target", tmpdir, "simple==1.0")
+    script.pip_install_local("--target", tmp_path, "simple==1.0")
 
     result = script.pip("list", "--user", "--format=json")
     json_result = json.loads(result.stdout)
     assert {"name": "simple2", "version": "3.0"} in json_result
 
-    result = script.pip("list", "--path", tmpdir, "--format=json")
+    result = script.pip("list", "--path", tmp_path, "--format=json")
     json_result = json.loads(result.stdout)
     assert {"name": "simple", "version": "1.0"} in json_result
 
 
 def test_list_path_multiple(
-    tmpdir: Path, script: PipTestEnvironment, data: TestData
+    tmp_path: pathlib.Path, script: PipTestEnvironment, data: TestData
 ) -> None:
     """
     Test list with multiple --path arguments.
     """
-    path1 = tmpdir / "path1"
-    os.mkdir(path1)
-    path2 = tmpdir / "path2"
-    os.mkdir(path2)
+    path1 = tmp_path / "path1"
+    path1.mkdir()
+    path2 = tmp_path / "path2"
+    path2.mkdir()
 
     script.pip_install_local("--target", path1, "simple==2.0")
     script.pip_install_local("--target", path2, "simple2==3.0")
@@ -690,7 +691,14 @@ def test_list_path_multiple(
     json_result = json.loads(result.stdout)
     assert {"name": "simple", "version": "2.0"} in json_result
 
-    result = script.pip("list", "--path", path1, "--path", path2, "--format=json")
+    result = script.pip(
+        "list",
+        "--path",
+        path1,
+        "--path",
+        path2,
+        "--format=json",
+    )
     json_result = json.loads(result.stdout)
     assert {"name": "simple", "version": "2.0"} in json_result
     assert {"name": "simple2", "version": "3.0"} in json_result
@@ -741,12 +749,10 @@ def test_list_pep610_editable(script: PipTestEnvironment) -> None:
     direct_url_path = get_created_direct_url_path(result, "testpkg")
     assert direct_url_path
     # patch direct_url.json to simulate an editable install
-    with open(direct_url_path) as f:
-        direct_url = DirectUrl.from_json(f.read())
+    direct_url = DirectUrl.from_json(direct_url_path.read_text())
     assert isinstance(direct_url.info, DirInfo)
     direct_url.info.editable = True
-    with open(direct_url_path, "w") as f:
-        f.write(direct_url.to_json())
+    direct_url_path.write_text(direct_url.to_json())
     result = script.pip("list", "--format=json")
     for item in json.loads(result.stdout):
         if item["name"] == "testpkg":
diff --git a/tests/functional/test_new_resolver.py b/tests/functional/test_new_resolver.py
index 7f35406f75f..9a8b78e68ae 100644
--- a/tests/functional/test_new_resolver.py
+++ b/tests/functional/test_new_resolver.py
@@ -11,15 +11,15 @@
     create_basic_sdist_for_package,
     create_basic_wheel_for_package,
     create_test_package_with_setup,
-    path_to_url,
 )
 from tests.lib.direct_url import get_created_direct_url
-from tests.lib.path import Path
 from tests.lib.wheel import make_wheel
 
 if TYPE_CHECKING:
     from typing import Protocol
 
+MakeFakeWheel = Callable[[str, str, str], pathlib.Path]
+
 
 def assert_editable(script: PipTestEnvironment, *args: str) -> None:
     # This simply checks whether all of the listed packages have a
@@ -32,8 +32,8 @@ def assert_editable(script: PipTestEnvironment, *args: str) -> None:
 
 
 @pytest.fixture()
-def make_fake_wheel(script: PipTestEnvironment) -> Callable[[str, str, str], Path]:
-    def _make_fake_wheel(name: str, version: str, wheel_tag: str) -> Path:
+def make_fake_wheel(script: PipTestEnvironment) -> MakeFakeWheel:
+    def _make_fake_wheel(name: str, version: str, wheel_tag: str) -> pathlib.Path:
         wheel_house = script.scratch_path.joinpath("wheelhouse")
         wheel_house.mkdir()
         wheel_builder = make_wheel(
@@ -221,9 +221,9 @@ def test_new_resolver_ignore_dependencies(script: PipTestEnvironment) -> None:
     ],
 )
 def test_new_resolver_installs_extras(
-    tmpdir: Path, script: PipTestEnvironment, root_dep: str
+    tmp_path: pathlib.Path, script: PipTestEnvironment, root_dep: str
 ) -> None:
-    req_file = tmpdir.joinpath("requirements.txt")
+    req_file = tmp_path.joinpath("requirements.txt")
     req_file.write_text(root_dep)
 
     create_basic_wheel_for_package(
@@ -379,7 +379,7 @@ def test_new_resolver_requires_python(
         "--no-cache-dir",
         "--no-index",
         "--find-links",
-        script.scratch_path,
+        os.fspath(script.scratch_path),
     ]
     if ignore_requires_python:
         args.append("--ignore-requires-python")
@@ -783,7 +783,7 @@ def test_new_resolver_constraint_on_path_empty(
         "--no-index",
         "-c",
         constraints_txt,
-        str(script.scratch_path),
+        script.scratch_path,
         expect_error=expect_error,
     )
 
@@ -938,13 +938,14 @@ def _local_with_setup(
     extras: Dict[str, List[str]],
 ) -> str:
     """Create the package as a local source directory to install from path."""
-    return create_test_package_with_setup(
+    path = create_test_package_with_setup(
         script,
         name=name,
         version=version,
         install_requires=requires,
         extras_require=extras,
     )
+    return str(path)
 
 
 def _direct_wheel(
@@ -955,13 +956,14 @@ def _direct_wheel(
     extras: Dict[str, List[str]],
 ) -> str:
     """Create the package as a wheel to install from path directly."""
-    return create_basic_wheel_for_package(
+    path = create_basic_wheel_for_package(
         script,
         name=name,
         version=version,
         depends=requires,
         extras=extras,
     )
+    return str(path)
 
 
 def _wheel_from_index(
@@ -1020,7 +1022,7 @@ def test_new_resolver_extra_merge_in_package(
             "--no-index",
             "--find-links",
             script.scratch_path,
-            requirement + "[dev]",
+            f"{requirement}[dev]",
         )
         script.assert_installed(pkg="1.0.0", dep="1.0.0", depdev="1.0.0")
 
@@ -1181,7 +1183,7 @@ def test_new_resolver_presents_messages_when_backtracking_a_lot(
     for index in range(1, N + 1):
         A_version = f"{index}.0.0"
         B_version = f"{index}.0.0"
-        C_version = "{index_minus_one}.0.0".format(index_minus_one=index - 1)
+        C_version = f"{index - 1}.0.0"
 
         depends = ["B == " + B_version]
         if index != 1:
@@ -1458,7 +1460,7 @@ def test_new_resolver_does_not_install_unneeded_packages_with_url_constraint(
     )
 
     constraints_file = script.scratch_path / "constraints.txt"
-    constraints_file.write_text("not_installed @ " + path_to_url(not_installed_path))
+    constraints_file.write_text(f"not_installed @ {not_installed_path.as_uri()}")
 
     (script.scratch_path / "index").mkdir()
     archive_path.rename(script.scratch_path / "index" / archive_path.name)
@@ -1488,10 +1490,15 @@ def test_new_resolver_installs_packages_with_url_constraint(
     )
 
     constraints_file = script.scratch_path / "constraints.txt"
-    constraints_file.write_text("installed @ " + path_to_url(installed_path))
+    constraints_file.write_text(f"installed @ {installed_path.as_uri()}")
 
     script.pip(
-        "install", "--no-cache-dir", "--no-index", "-c", constraints_file, "installed"
+        "install",
+        "--no-cache-dir",
+        "--no-index",
+        "-c",
+        constraints_file,
+        "installed",
     )
 
     script.assert_installed(installed="0.1.0")
@@ -1507,7 +1514,7 @@ def test_new_resolver_reinstall_link_requirement_with_constraint(
     )
 
     cr_file = script.scratch_path / "constraints.txt"
-    cr_file.write_text("installed @ " + path_to_url(installed_path))
+    cr_file.write_text(f"installed @ {installed_path.as_uri()}")
 
     script.pip(
         "install",
@@ -1545,7 +1552,7 @@ def test_new_resolver_prefers_url_constraint(script: PipTestEnvironment) -> None
     )
 
     constraints_file = script.scratch_path / "constraints.txt"
-    constraints_file.write_text("test_pkg @ " + path_to_url(installed_path))
+    constraints_file.write_text(f"test_pkg @ {installed_path.as_uri()}")
 
     (script.scratch_path / "index").mkdir()
     not_installed_path.rename(script.scratch_path / "index" / not_installed_path.name)
@@ -1579,7 +1586,7 @@ def test_new_resolver_prefers_url_constraint_on_update(
     )
 
     constraints_file = script.scratch_path / "constraints.txt"
-    constraints_file.write_text("test_pkg @ " + path_to_url(installed_path))
+    constraints_file.write_text(f"test_pkg @ {installed_path.as_uri()}")
 
     (script.scratch_path / "index").mkdir()
     not_installed_path.rename(script.scratch_path / "index" / not_installed_path.name)
@@ -1626,7 +1633,7 @@ def test_new_resolver_fails_with_url_constraint_and_incompatible_version(
     )
 
     url_constraint = script.scratch_path / "constraints.txt"
-    url_constraint.write_text("test_pkg @ " + path_to_url(not_installed_path))
+    url_constraint.write_text(f"test_pkg @ {not_installed_path.as_uri()}")
 
     version_req = script.scratch_path / "requirements.txt"
     version_req.write_text("test_pkg<0.2.0")
@@ -1685,8 +1692,8 @@ def test_new_resolver_ignores_unneeded_conflicting_constraints(
     )
 
     constraints = [
-        "test_pkg @ " + path_to_url(version_1),
-        "test_pkg @ " + path_to_url(version_2),
+        f"test_pkg @ {version_1.as_uri()}",
+        f"test_pkg @ {version_2.as_uri()}",
     ]
 
     constraints_file = script.scratch_path / "constraints.txt"
@@ -1722,8 +1729,8 @@ def test_new_resolver_fails_on_needed_conflicting_constraints(
     )
 
     constraints = [
-        "test_pkg @ " + path_to_url(version_1),
-        "test_pkg @ " + path_to_url(version_2),
+        f"test_pkg @ {version_1.as_uri()}",
+        f"test_pkg @ {version_2.as_uri()}",
     ]
 
     constraints_file = script.scratch_path / "constraints.txt"
@@ -1774,7 +1781,7 @@ def test_new_resolver_fails_on_conflicting_constraint_and_requirement(
     )
 
     constraints_file = script.scratch_path / "constraints.txt"
-    constraints_file.write_text("test_pkg @ " + path_to_url(version_1))
+    constraints_file.write_text(f"test_pkg @ {version_1.as_uri()}")
 
     result = script.pip(
         "install",
@@ -1784,7 +1791,7 @@ def test_new_resolver_fails_on_conflicting_constraint_and_requirement(
         script.scratch_path,
         "-c",
         constraints_file,
-        "test_pkg @ " + path_to_url(version_2),
+        f"test_pkg @ {version_2.as_uri()}",
         expect_error=True,
     )
 
@@ -1802,7 +1809,7 @@ def test_new_resolver_fails_on_conflicting_constraint_and_requirement(
         "--no-index",
         "--find-links",
         script.scratch_path,
-        "test_pkg @ " + path_to_url(version_2),
+        f"test_pkg @ {version_2.as_uri()}",
     )
 
 
@@ -1821,14 +1828,14 @@ def test_new_resolver_succeeds_on_matching_constraint_and_requirement(
             "0.1.0",
         )
 
-    req_line = "test_pkg @ " + path_to_url(source_dir)
+    req_line = f"test_pkg @ {source_dir.as_uri()}"
 
     constraints_file = script.scratch_path / "constraints.txt"
     constraints_file.write_text(req_line)
 
     last_args: Tuple[str, ...]
     if editable:
-        last_args = ("-e", source_dir)
+        last_args = ("-e", str(source_dir))
     else:
         last_args = (req_line,)
 
@@ -1865,7 +1872,7 @@ def test_new_resolver_applies_url_constraint_to_dep(script: PipTestEnvironment)
     version_2.rename(script.scratch_path / "index" / version_2.name)
 
     constraints_file = script.scratch_path / "constraints.txt"
-    constraints_file.write_text("dep @ " + path_to_url(version_1))
+    constraints_file.write_text(f"dep @ {version_1.as_uri()}")
 
     script.pip(
         "install",
@@ -1882,7 +1889,7 @@ def test_new_resolver_applies_url_constraint_to_dep(script: PipTestEnvironment)
 
 
 def test_new_resolver_handles_compatible_wheel_tags_in_constraint_url(
-    script: PipTestEnvironment, make_fake_wheel: Callable[[str, str, str], Path]
+    script: PipTestEnvironment, make_fake_wheel: MakeFakeWheel
 ) -> None:
     initial_path = make_fake_wheel("base", "0.1.0", "fakepy1-fakeabi-fakeplat")
 
@@ -1894,7 +1901,7 @@ def test_new_resolver_handles_compatible_wheel_tags_in_constraint_url(
     initial_path.rename(final_path)
 
     constraints_file = script.scratch_path / "constraints.txt"
-    constraints_file.write_text("base @ " + path_to_url(final_path))
+    constraints_file.write_text(f"base @ {final_path.as_uri()}")
 
     result = script.pip(
         "install",
@@ -1916,12 +1923,11 @@ def test_new_resolver_handles_compatible_wheel_tags_in_constraint_url(
         "base",
     )
 
-    dist_info = Path("scratch", "target", "base-0.1.0.dist-info")
-    result.did_create(dist_info)
+    result.did_create("scratch/target/base-0.1.0.dist-info")
 
 
 def test_new_resolver_handles_incompatible_wheel_tags_in_constraint_url(
-    script: PipTestEnvironment, make_fake_wheel: Callable[[str, str, str], Path]
+    script: PipTestEnvironment, make_fake_wheel: MakeFakeWheel
 ) -> None:
     initial_path = make_fake_wheel("base", "0.1.0", "fakepy1-fakeabi-fakeplat")
 
@@ -1933,7 +1939,7 @@ def test_new_resolver_handles_incompatible_wheel_tags_in_constraint_url(
     initial_path.rename(final_path)
 
     constraints_file = script.scratch_path / "constraints.txt"
-    constraints_file.write_text("base @ " + path_to_url(final_path))
+    constraints_file.write_text(f"base @ {final_path.as_uri()}")
 
     result = script.pip(
         "install",
@@ -1954,7 +1960,7 @@ def test_new_resolver_handles_incompatible_wheel_tags_in_constraint_url(
 
 
 def test_new_resolver_avoids_incompatible_wheel_tags_in_constraint_url(
-    script: PipTestEnvironment, make_fake_wheel: Callable[[str, str, str], Path]
+    script: PipTestEnvironment, make_fake_wheel: MakeFakeWheel
 ) -> None:
     initial_path = make_fake_wheel("dep", "0.1.0", "fakepy1-fakeabi-fakeplat")
 
@@ -1966,7 +1972,7 @@ def test_new_resolver_avoids_incompatible_wheel_tags_in_constraint_url(
     initial_path.rename(final_path)
 
     constraints_file = script.scratch_path / "constraints.txt"
-    constraints_file.write_text("dep @ " + path_to_url(final_path))
+    constraints_file.write_text(f"dep @ {final_path.as_uri()}")
 
     index = script.scratch_path / "index"
     index.mkdir()
@@ -2060,7 +2066,7 @@ def test_new_resolver_direct_url_equivalent(
         script,
         name="pkgb",
         version="1",
-        depends=[f"pkga@{path_to_url(pkga)}{depend_suffix}"],
+        depends=[f"pkga@{pkga.as_uri()}{depend_suffix}"],
     )
 
     # Make pkgb visible via --find-links, but not pkga.
@@ -2076,8 +2082,8 @@ def test_new_resolver_direct_url_equivalent(
         "--no-cache-dir",
         "--no-index",
         "--find-links",
-        str(find_links),
-        f"{path_to_url(pkga)}{request_suffix}",
+        find_links,
+        f"{pkga.as_uri()}{request_suffix}",
         "pkgb",
         expect_error=(not suffixes_equivalent),
     )
@@ -2120,7 +2126,7 @@ def test_new_resolver_direct_url_with_extras(
         "--no-cache-dir",
         "--no-index",
         "--find-links",
-        str(find_links),
+        find_links,
         pkg2,
         "pkg3",
     )
@@ -2200,35 +2206,30 @@ def test_new_resolver_transitively_depends_on_unnamed_local(
     )
 
 
-def _to_uri(path: str) -> str:
-    # Something like file:///path/to/package
-    return pathlib.Path(path).as_uri()
-
-
-def _to_localhost_uri(path: str) -> str:
+def _to_localhost_uri(path: pathlib.Path) -> str:
     # Something like file://localhost/path/to/package
-    return pathlib.Path(path).as_uri().replace("///", "//localhost/")
+    return path.as_uri().replace("///", "//localhost/")
 
 
 @pytest.mark.parametrize(
     "format_dep",
     [
-        pytest.param(_to_uri, id="emptyhost"),
+        pytest.param(pathlib.Path.as_uri, id="emptyhost"),
         pytest.param(_to_localhost_uri, id="localhost"),
     ],
 )
 @pytest.mark.parametrize(
     "format_input",
     [
-        pytest.param(lambda path: path, id="path"),
-        pytest.param(_to_uri, id="emptyhost"),
+        pytest.param(pathlib.Path, id="path"),
+        pytest.param(pathlib.Path.as_uri, id="emptyhost"),
         pytest.param(_to_localhost_uri, id="localhost"),
     ],
 )
 def test_new_resolver_file_url_normalize(
     script: PipTestEnvironment,
-    format_dep: Callable[[str], str],
-    format_input: Callable[[str], str],
+    format_dep: Callable[[pathlib.Path], str],
+    format_input: Callable[[pathlib.Path], str],
 ) -> None:
     lib_a = create_test_package_with_setup(
         script,
diff --git a/tests/functional/test_new_resolver_errors.py b/tests/functional/test_new_resolver_errors.py
index 1278bc3edde..11ac6a29f58 100644
--- a/tests/functional/test_new_resolver_errors.py
+++ b/tests/functional/test_new_resolver_errors.py
@@ -6,11 +6,10 @@
     create_basic_wheel_for_package,
     create_test_package_with_setup,
 )
-from tests.lib.path import Path
 
 
 def test_new_resolver_conflict_requirements_file(
-    tmpdir: Path, script: PipTestEnvironment
+    tmp_path: pathlib.Path, script: PipTestEnvironment
 ) -> None:
     create_basic_wheel_for_package(script, "base", "1.0")
     create_basic_wheel_for_package(script, "base", "2.0")
@@ -27,7 +26,7 @@ def test_new_resolver_conflict_requirements_file(
         depends=["base==2.0"],
     )
 
-    req_file = tmpdir.joinpath("requirements.txt")
+    req_file = tmp_path.joinpath("requirements.txt")
     req_file.write_text("pkga\npkgb")
 
     result = script.pip(
@@ -46,11 +45,11 @@ def test_new_resolver_conflict_requirements_file(
 
 
 def test_new_resolver_conflict_constraints_file(
-    tmpdir: Path, script: PipTestEnvironment
+    tmp_path: pathlib.Path, script: PipTestEnvironment
 ) -> None:
     create_basic_wheel_for_package(script, "pkg", "1.0")
 
-    constraints_file = tmpdir.joinpath("constraints.txt")
+    constraints_file = tmp_path.joinpath("constraints.txt")
     constraints_file.write_text("pkg!=1.0")
 
     result = script.pip(
@@ -89,7 +88,13 @@ def test_new_resolver_requires_python_error(script: PipTestEnvironment) -> None:
     )
 
     # This always fails because pkgb can never be satisfied.
-    result = script.pip("install", "--no-index", pkga, pkgb, expect_error=True)
+    result = script.pip(
+        "install",
+        "--no-index",
+        pkga,
+        pkgb,
+        expect_error=True,
+    )
 
     # The error message should mention the Requires-Python: value causing the
     # conflict, not the compatible one.
diff --git a/tests/functional/test_new_resolver_hashes.py b/tests/functional/test_new_resolver_hashes.py
index 80ed86219d4..c443853c128 100644
--- a/tests/functional/test_new_resolver_hashes.py
+++ b/tests/functional/test_new_resolver_hashes.py
@@ -1,19 +1,20 @@
-import collections
 import hashlib
+import pathlib
+from typing import NamedTuple
 
 import pytest
 
-from pip._internal.utils.urls import path_to_url
 from tests.lib import (
     PipTestEnvironment,
     create_basic_sdist_for_package,
     create_basic_wheel_for_package,
 )
 
-_FindLinks = collections.namedtuple(
-    "_FindLinks",
-    "index_html sdist_hash wheel_hash",
-)
+
+class _FindLinks(NamedTuple):
+    index_html: pathlib.Path
+    sdist_hash: str
+    wheel_hash: str
 
 
 def _create_find_links(script: PipTestEnvironment) -> _FindLinks:
@@ -30,10 +31,10 @@ def _create_find_links(script: PipTestEnvironment) -> _FindLinks:
         <a href="{sdist_url}#sha256={sdist_hash}">{sdist_path.stem}</a>
         <a href="{wheel_url}#sha256={wheel_hash}">{wheel_path.stem}</a>
         """.format(
-            sdist_url=path_to_url(sdist_path),
+            sdist_url=sdist_path.as_uri(),
             sdist_hash=sdist_hash,
             sdist_path=sdist_path,
-            wheel_url=path_to_url(wheel_path),
+            wheel_url=wheel_path.as_uri(),
             wheel_hash=wheel_hash,
             wheel_path=wheel_path,
         ).strip()
@@ -249,7 +250,7 @@ def test_new_resolver_hash_requirement_and_url_constraint_can_succeed(
     )
 
     constraints_txt = script.scratch_path / "constraints.txt"
-    constraint_text = "base @ {wheel_url}\n".format(wheel_url=path_to_url(wheel_path))
+    constraint_text = "base @ {wheel_url}\n".format(wheel_url=wheel_path.as_uri())
     if constrain_by_hash:
         constraint_text += "base==0.1.0 --hash=sha256:{wheel_hash}\n".format(
             wheel_hash=wheel_hash,
@@ -289,7 +290,7 @@ def test_new_resolver_hash_requirement_and_url_constraint_can_fail(
     )
 
     constraints_txt = script.scratch_path / "constraints.txt"
-    constraint_text = "base @ {wheel_url}\n".format(wheel_url=path_to_url(wheel_path))
+    constraint_text = "base @ {wheel_url}\n".format(wheel_url=wheel_path.as_uri())
     if constrain_by_hash:
         constraint_text += "base==0.1.0 --hash=sha256:{other_hash}\n".format(
             other_hash=other_hash,
diff --git a/tests/functional/test_new_resolver_target.py b/tests/functional/test_new_resolver_target.py
index 398695b5a83..15e688f6a64 100644
--- a/tests/functional/test_new_resolver_target.py
+++ b/tests/functional/test_new_resolver_target.py
@@ -1,18 +1,18 @@
+import pathlib
 from typing import Callable, Optional
 
 import pytest
 
 from pip._internal.cli.status_codes import ERROR, SUCCESS
 from tests.lib import PipTestEnvironment
-from tests.lib.path import Path
 from tests.lib.wheel import make_wheel
 
-MakeFakeWheel = Callable[[str], Path]
+MakeFakeWheel = Callable[[str], pathlib.Path]
 
 
 @pytest.fixture()
 def make_fake_wheel(script: PipTestEnvironment) -> MakeFakeWheel:
-    def _make_fake_wheel(wheel_tag: str) -> Path:
+    def _make_fake_wheel(wheel_tag: str) -> pathlib.Path:
         wheel_house = script.scratch_path.joinpath("wheelhouse")
         wheel_house.mkdir()
         wheel_builder = make_wheel(
@@ -47,7 +47,7 @@ def test_new_resolver_target_checks_compatibility_failure(
         "--no-index",
         "--target",
         str(script.scratch_path.joinpath("target")),
-        make_fake_wheel(fake_wheel_tag),
+        str(make_fake_wheel(fake_wheel_tag)),
     ]
     if implementation:
         args += ["--implementation", implementation]
@@ -68,7 +68,7 @@ def test_new_resolver_target_checks_compatibility_failure(
 
     result = script.pip(*args, expect_error=(not wheel_tag_matches))
 
-    dist_info = Path("scratch", "target", "fake-1.0.dist-info")
+    dist_info = pathlib.Path("scratch", "target", "fake-1.0.dist-info")
     if wheel_tag_matches:
         assert result.returncode == SUCCESS
         result.did_create(dist_info)
diff --git a/tests/functional/test_new_resolver_user.py b/tests/functional/test_new_resolver_user.py
index acdae71c9cf..4a667d3f324 100644
--- a/tests/functional/test_new_resolver_user.py
+++ b/tests/functional/test_new_resolver_user.py
@@ -173,7 +173,7 @@ def test_new_resolver_install_user_reinstall_global_site(
 
     result.did_create(script.user_site / "base")
 
-    site_packages_content = set(os.listdir(script.site_packages_path))
+    site_packages_content = {p.name for p in script.site_packages_path.iterdir()}
     assert "base" in site_packages_content
 
 
@@ -211,7 +211,7 @@ def test_new_resolver_install_user_conflict_in_global_site(
     base_2_dist_info = script.user_site / "base-2.0.0.dist-info"
     result.did_create(base_2_dist_info)
 
-    site_packages_content = set(os.listdir(script.site_packages_path))
+    site_packages_content = {p.name for p in script.site_packages_path.iterdir()}
     assert "base-1.0.0.dist-info" in site_packages_content
 
 
@@ -262,5 +262,5 @@ def test_new_resolver_install_user_conflict_in_global_and_user_sites(
     result.did_create(base_1_dist_info)
     assert base_2_dist_info in result.files_deleted, str(result)
 
-    site_packages_content = set(os.listdir(script.site_packages_path))
+    site_packages_content = {p.name for p in script.site_packages_path.iterdir()}
     assert "base-2.0.0.dist-info" in site_packages_content
diff --git a/tests/functional/test_pep517.py b/tests/functional/test_pep517.py
index 7f913c21584..bbae63f5afb 100644
--- a/tests/functional/test_pep517.py
+++ b/tests/functional/test_pep517.py
@@ -1,3 +1,4 @@
+import pathlib
 from typing import Any, Dict, List, Optional, Tuple
 
 import pytest
@@ -10,19 +11,17 @@
     TestData,
     create_basic_wheel_for_package,
     make_test_finder,
-    path_to_url,
 )
-from tests.lib.path import Path
 
 
 def make_project(
-    tmpdir: Path,
+    tmp_path: pathlib.Path,
     requires: Optional[List[str]] = None,
     backend: Optional[str] = None,
     backend_path: Optional[List[str]] = None,
-) -> Path:
+) -> pathlib.Path:
     requires = requires or []
-    project_dir = tmpdir / "project"
+    project_dir = tmp_path / "project"
     project_dir.mkdir()
     buildsys: Dict[str, Any] = {"requires": requires}
     if backend:
@@ -34,11 +33,11 @@ def make_project(
     return project_dir
 
 
-def test_backend(tmpdir: Path, data: TestData) -> None:
+def test_backend(tmp_path: pathlib.Path, data: TestData) -> None:
     """Check we can call a requirement's backend successfully"""
-    project_dir = make_project(tmpdir, backend="dummy_backend")
+    project_dir = make_project(tmp_path, backend="dummy_backend")
     req = InstallRequirement(None, None)
-    req.source_dir = project_dir  # make req believe it has been unpacked
+    req.source_dir = str(project_dir)  # make req believe it has been unpacked
     req.load_pyproject_toml()
     env = BuildEnvironment()
     finder = make_test_finder(find_links=[data.backends])
@@ -61,12 +60,13 @@ def build_wheel(
 """
 
 
-def test_backend_path(tmpdir: Path, data: TestData) -> None:
+@pytest.mark.usefixtures("data")
+def test_backend_path(tmp_path: pathlib.Path) -> None:
     """Check we can call a backend inside the project"""
-    project_dir = make_project(tmpdir, backend="dummy_backend", backend_path=["."])
+    project_dir = make_project(tmp_path, backend="dummy_backend", backend_path=["."])
     (project_dir / "dummy_backend.py").write_text(dummy_backend_code)
     req = InstallRequirement(None, None)
-    req.source_dir = project_dir  # make req believe it has been unpacked
+    req.source_dir = str(project_dir)  # make req believe it has been unpacked
     req.load_pyproject_toml()
 
     env = BuildEnvironment()
@@ -76,16 +76,16 @@ def test_backend_path(tmpdir: Path, data: TestData) -> None:
         assert req.pep517_backend.build_wheel("dir") == "Backend called"
 
 
-def test_backend_path_and_dep(tmpdir: Path, data: TestData) -> None:
+def test_backend_path_and_dep(tmp_path: pathlib.Path, data: TestData) -> None:
     """Check we can call a requirement's backend successfully"""
     project_dir = make_project(
-        tmpdir, backend="dummy_internal_backend", backend_path=["."]
+        tmp_path, backend="dummy_internal_backend", backend_path=["."]
     )
     (project_dir / "dummy_internal_backend.py").write_text(
         "from dummy_backend import build_wheel"
     )
     req = InstallRequirement(None, None)
-    req.source_dir = project_dir  # make req believe it has been unpacked
+    req.source_dir = str(project_dir)  # make req believe it has been unpacked
     req.load_pyproject_toml()
     env = BuildEnvironment()
     finder = make_test_finder(find_links=[data.backends])
@@ -98,36 +98,42 @@ def test_backend_path_and_dep(tmpdir: Path, data: TestData) -> None:
 
 
 def test_pep517_install(
-    script: PipTestEnvironment, tmpdir: Path, data: TestData
+    script: PipTestEnvironment, tmp_path: pathlib.Path, data: TestData
 ) -> None:
     """Check we can build with a custom backend"""
     project_dir = make_project(
-        tmpdir, requires=["test_backend"], backend="test_backend"
+        tmp_path, requires=["test_backend"], backend="test_backend"
     )
     result = script.pip("install", "--no-index", "-f", data.backends, project_dir)
     result.assert_installed("project", editable=False)
 
 
 def test_pep517_install_with_reqs(
-    script: PipTestEnvironment, tmpdir: Path, data: TestData
+    script: PipTestEnvironment, tmp_path: pathlib.Path, data: TestData
 ) -> None:
     """Backend generated requirements are installed in the build env"""
     project_dir = make_project(
-        tmpdir, requires=["test_backend"], backend="test_backend"
+        tmp_path, requires=["test_backend"], backend="test_backend"
     )
     project_dir.joinpath("backend_reqs.txt").write_text("simplewheel")
     result = script.pip(
-        "install", "--no-index", "-f", data.backends, "-f", data.packages, project_dir
+        "install",
+        "--no-index",
+        "-f",
+        data.backends,
+        "-f",
+        data.packages,
+        project_dir,
     )
     result.assert_installed("project", editable=False)
 
 
 def test_no_use_pep517_without_setup_py(
-    script: PipTestEnvironment, tmpdir: Path, data: TestData
+    script: PipTestEnvironment, tmp_path: pathlib.Path, data: TestData
 ) -> None:
     """Using --no-use-pep517 requires setup.py"""
     project_dir = make_project(
-        tmpdir, requires=["test_backend"], backend="test_backend"
+        tmp_path, requires=["test_backend"], backend="test_backend"
     )
     result = script.pip(
         "install",
@@ -142,10 +148,10 @@ def test_no_use_pep517_without_setup_py(
 
 
 def test_conflicting_pep517_backend_requirements(
-    script: PipTestEnvironment, tmpdir: Path, data: TestData
+    script: PipTestEnvironment, tmp_path: pathlib.Path, data: TestData
 ) -> None:
     project_dir = make_project(
-        tmpdir, requires=["test_backend", "simplewheel==1.0"], backend="test_backend"
+        tmp_path, requires=["test_backend", "simplewheel==1.0"], backend="test_backend"
     )
     project_dir.joinpath("backend_reqs.txt").write_text("simplewheel==2.0")
     result = script.pip(
@@ -161,16 +167,16 @@ def test_conflicting_pep517_backend_requirements(
     msg = (
         "Some build dependencies for {url} conflict with the backend "
         "dependencies: simplewheel==1.0 is incompatible with "
-        "simplewheel==2.0.".format(url=path_to_url(project_dir))
+        "simplewheel==2.0.".format(url=project_dir.as_uri())
     )
     assert result.returncode != 0 and msg in result.stderr, str(result)
 
 
 def test_no_check_build_deps(
-    script: PipTestEnvironment, tmpdir: Path, data: TestData
+    script: PipTestEnvironment, tmp_path: pathlib.Path, data: TestData
 ) -> None:
     project_dir = make_project(
-        tmpdir, requires=["simplewheel==2.0"], backend="test_backend"
+        tmp_path, requires=["simplewheel==2.0"], backend="test_backend"
     )
     script.pip(
         "install",
@@ -187,10 +193,10 @@ def test_no_check_build_deps(
 
 
 def test_validate_missing_pep517_backend_requirements(
-    script: PipTestEnvironment, tmpdir: Path, data: TestData
+    script: PipTestEnvironment, tmp_path: pathlib.Path, data: TestData
 ) -> None:
     project_dir = make_project(
-        tmpdir, requires=["test_backend", "simplewheel==1.0"], backend="test_backend"
+        tmp_path, requires=["test_backend", "simplewheel==1.0"], backend="test_backend"
     )
     result = script.pip(
         "install",
@@ -206,16 +212,16 @@ def test_validate_missing_pep517_backend_requirements(
     )
     msg = (
         "Some build dependencies for {url} are missing: "
-        "'simplewheel==1.0', 'test_backend'.".format(url=path_to_url(project_dir))
+        "'simplewheel==1.0', 'test_backend'.".format(url=project_dir.as_uri())
     )
     assert result.returncode != 0 and msg in result.stderr, str(result)
 
 
 def test_validate_conflicting_pep517_backend_requirements(
-    script: PipTestEnvironment, tmpdir: Path, data: TestData
+    script: PipTestEnvironment, tmp_path: pathlib.Path, data: TestData
 ) -> None:
     project_dir = make_project(
-        tmpdir, requires=["simplewheel==1.0"], backend="test_backend"
+        tmp_path, requires=["simplewheel==1.0"], backend="test_backend"
     )
     script.pip("install", "simplewheel==2.0", "--no-index", "-f", data.packages)
     result = script.pip(
@@ -233,7 +239,7 @@ def test_validate_conflicting_pep517_backend_requirements(
     msg = (
         "Some build dependencies for {url} conflict with the backend "
         "dependencies: simplewheel==2.0 is incompatible with "
-        "simplewheel==1.0.".format(url=path_to_url(project_dir))
+        "simplewheel==1.0.".format(url=project_dir.as_uri())
     )
     assert result.returncode != 0 and msg in result.stderr, str(result)
 
@@ -253,15 +259,20 @@ def test_pep517_backend_requirements_satisfied_by_prerelease(
     )
     project_dir.joinpath("backend_reqs.txt").write_text("myreq")
 
-    result = script.pip("install", "--no-index", "--no-build-isolation", project_dir)
+    result = script.pip(
+        "install",
+        "--no-index",
+        "--no-build-isolation",
+        project_dir,
+    )
     assert "Installing backend dependencies:" not in result.stdout
 
 
 def test_pep517_backend_requirements_already_satisfied(
-    script: PipTestEnvironment, tmpdir: Path, data: TestData
+    script: PipTestEnvironment, tmp_path: pathlib.Path, data: TestData
 ) -> None:
     project_dir = make_project(
-        tmpdir, requires=["test_backend", "simplewheel==1.0"], backend="test_backend"
+        tmp_path, requires=["test_backend", "simplewheel==1.0"], backend="test_backend"
     )
     project_dir.joinpath("backend_reqs.txt").write_text("simplewheel")
     result = script.pip(
@@ -277,11 +288,11 @@ def test_pep517_backend_requirements_already_satisfied(
 
 
 def test_pep517_install_with_no_cache_dir(
-    script: PipTestEnvironment, tmpdir: Path, data: TestData
+    script: PipTestEnvironment, tmp_path: pathlib.Path, data: TestData
 ) -> None:
     """Check builds with a custom backends work, even with no cache."""
     project_dir = make_project(
-        tmpdir, requires=["test_backend"], backend="test_backend"
+        tmp_path, requires=["test_backend"], backend="test_backend"
     )
     result = script.pip(
         "install",
@@ -295,9 +306,9 @@ def test_pep517_install_with_no_cache_dir(
 
 
 def make_pyproject_with_setup(
-    tmpdir: Path, build_system: bool = True, set_backend: bool = True
-) -> Tuple[Path, str]:
-    project_dir = tmpdir / "project"
+    tmp_path: pathlib.Path, build_system: bool = True, set_backend: bool = True
+) -> Tuple[pathlib.Path, str]:
+    project_dir = tmp_path / "project"
     project_dir.mkdir()
     setup_script = "from setuptools import setup\n"
     expect_script_dir_on_path = True
@@ -334,11 +345,14 @@ def make_pyproject_with_setup(
     return project_dir, "pep517_test"
 
 
+@pytest.mark.usefixtures("data")
 def test_no_build_system_section(
-    script: PipTestEnvironment, tmpdir: Path, data: TestData, common_wheels: Path
+    script: PipTestEnvironment,
+    tmp_path: pathlib.Path,
+    common_wheels: pathlib.Path,
 ) -> None:
     """Check builds with setup.py, pyproject.toml, but no build-system section."""
-    project_dir, name = make_pyproject_with_setup(tmpdir, build_system=False)
+    project_dir, name = make_pyproject_with_setup(tmp_path, build_system=False)
     result = script.pip(
         "install",
         "--no-cache-dir",
@@ -350,11 +364,14 @@ def test_no_build_system_section(
     result.assert_installed(name, editable=False)
 
 
+@pytest.mark.usefixtures("data")
 def test_no_build_backend_entry(
-    script: PipTestEnvironment, tmpdir: Path, data: TestData, common_wheels: Path
+    script: PipTestEnvironment,
+    tmp_path: pathlib.Path,
+    common_wheels: pathlib.Path,
 ) -> None:
     """Check builds with setup.py, pyproject.toml, but no build-backend entry."""
-    project_dir, name = make_pyproject_with_setup(tmpdir, set_backend=False)
+    project_dir, name = make_pyproject_with_setup(tmp_path, set_backend=False)
     result = script.pip(
         "install",
         "--no-cache-dir",
@@ -366,11 +383,14 @@ def test_no_build_backend_entry(
     result.assert_installed(name, editable=False)
 
 
+@pytest.mark.usefixtures("data")
 def test_explicit_setuptools_backend(
-    script: PipTestEnvironment, tmpdir: Path, data: TestData, common_wheels: Path
+    script: PipTestEnvironment,
+    tmp_path: pathlib.Path,
+    common_wheels: pathlib.Path,
 ) -> None:
     """Check builds with setup.py, pyproject.toml, and a build-backend entry."""
-    project_dir, name = make_pyproject_with_setup(tmpdir)
+    project_dir, name = make_pyproject_with_setup(tmp_path)
     result = script.pip(
         "install",
         "--no-cache-dir",
@@ -383,15 +403,18 @@ def test_explicit_setuptools_backend(
 
 
 @pytest.mark.network
+@pytest.mark.usefixtures("data")
 def test_pep517_and_build_options(
-    script: PipTestEnvironment, tmpdir: Path, data: TestData, common_wheels: Path
+    script: PipTestEnvironment,
+    tmp_path: pathlib.Path,
+    common_wheels: pathlib.Path,
 ) -> None:
     """Backend generated requirements are installed in the build env"""
-    project_dir, name = make_pyproject_with_setup(tmpdir)
+    project_dir, _ = make_pyproject_with_setup(tmp_path)
     result = script.pip(
         "wheel",
         "--wheel-dir",
-        tmpdir,
+        tmp_path,
         "--build-option",
         "foo",
         "-f",
@@ -404,15 +427,18 @@ def test_pep517_and_build_options(
 
 
 @pytest.mark.network
+@pytest.mark.usefixtures("data")
 def test_pep517_and_global_options(
-    script: PipTestEnvironment, tmpdir: Path, data: TestData, common_wheels: Path
+    script: PipTestEnvironment,
+    tmp_path: pathlib.Path,
+    common_wheels: pathlib.Path,
 ) -> None:
     """Backend generated requirements are installed in the build env"""
-    project_dir, name = make_pyproject_with_setup(tmpdir)
+    project_dir, _ = make_pyproject_with_setup(tmp_path)
     result = script.pip(
         "wheel",
         "--wheel-dir",
-        tmpdir,
+        tmp_path,
         "--global-option",
         "foo",
         "-f",
diff --git a/tests/functional/test_pep660.py b/tests/functional/test_pep660.py
index c55fb80d37b..4fe0f2f7819 100644
--- a/tests/functional/test_pep660.py
+++ b/tests/functional/test_pep660.py
@@ -1,12 +1,11 @@
 import os
+import pathlib
 from typing import Any, Dict
 
 import pytest
 import tomli_w
 
-from pip._internal.utils.urls import path_to_url
 from tests.lib import PipTestEnvironment
-from tests.lib.path import Path
 
 SETUP_PY = """
 from setuptools import setup
@@ -64,9 +63,12 @@ def build_editable(wheel_directory, config_settings=None, metadata_directory=Non
 
 
 def _make_project(
-    tmpdir: Path, backend_code: str, with_setup_py: bool, with_pyproject: bool = True
-) -> Path:
-    project_dir = tmpdir / "project"
+    tmp_path: pathlib.Path,
+    backend_code: str,
+    with_setup_py: bool,
+    with_pyproject: bool = True,
+) -> pathlib.Path:
+    project_dir = tmp_path / "project"
     project_dir.mkdir()
     project_dir.joinpath("setup.cfg").write_text(SETUP_CFG)
     if with_setup_py:
@@ -85,22 +87,25 @@ def _make_project(
     return project_dir
 
 
-def _assert_hook_called(project_dir: Path, hook: str) -> None:
+def _assert_hook_called(project_dir: pathlib.Path, hook: str) -> None:
     log = project_dir.joinpath("log.txt").read_text()
     assert f":{hook} called" in log, f"{hook} has not been called"
 
 
-def _assert_hook_not_called(project_dir: Path, hook: str) -> None:
+def _assert_hook_not_called(project_dir: pathlib.Path, hook: str) -> None:
     log = project_dir.joinpath("log.txt").read_text()
     assert f":{hook} called" not in log, f"{hook} should not have been called"
 
 
 @pytest.mark.usefixtures("with_wheel")
-def test_install_pep517_basic(tmpdir: Path, script: PipTestEnvironment) -> None:
+def test_install_pep517_basic(
+    tmp_path: pathlib.Path,
+    script: PipTestEnvironment,
+) -> None:
     """
     Check that the test harness we have in this file is sane.
     """
-    project_dir = _make_project(tmpdir, BACKEND_WITHOUT_PEP660, with_setup_py=False)
+    project_dir = _make_project(tmp_path, BACKEND_WITHOUT_PEP660, with_setup_py=False)
     script.pip(
         "install",
         "--no-index",
@@ -112,11 +117,14 @@ def test_install_pep517_basic(tmpdir: Path, script: PipTestEnvironment) -> None:
 
 
 @pytest.mark.usefixtures("with_wheel")
-def test_install_pep660_basic(tmpdir: Path, script: PipTestEnvironment) -> None:
+def test_install_pep660_basic(
+    tmp_path: pathlib.Path,
+    script: PipTestEnvironment,
+) -> None:
     """
     Test with backend that supports build_editable.
     """
-    project_dir = _make_project(tmpdir, BACKEND_WITH_PEP660, with_setup_py=False)
+    project_dir = _make_project(tmp_path, BACKEND_WITH_PEP660, with_setup_py=False)
     result = script.pip(
         "install",
         "--no-index",
@@ -134,14 +142,14 @@ def test_install_pep660_basic(tmpdir: Path, script: PipTestEnvironment) -> None:
 
 @pytest.mark.usefixtures("with_wheel")
 def test_install_no_pep660_setup_py_fallback(
-    tmpdir: Path, script: PipTestEnvironment
+    tmp_path: pathlib.Path, script: PipTestEnvironment
 ) -> None:
     """
     Test that we fall back to setuptools develop when using a backend that
     does not support build_editable. Since there is a pyproject.toml,
     the prepare_metadata_for_build_wheel hook is called.
     """
-    project_dir = _make_project(tmpdir, BACKEND_WITHOUT_PEP660, with_setup_py=True)
+    project_dir = _make_project(tmp_path, BACKEND_WITHOUT_PEP660, with_setup_py=True)
     result = script.pip(
         "install",
         "--no-index",
@@ -159,14 +167,14 @@ def test_install_no_pep660_setup_py_fallback(
 
 @pytest.mark.usefixtures("with_wheel")
 def test_install_no_pep660_setup_cfg_fallback(
-    tmpdir: Path, script: PipTestEnvironment
+    tmp_path: pathlib.Path, script: PipTestEnvironment
 ) -> None:
     """
     Test that we fall back to setuptools develop when using a backend that
     does not support build_editable. Since there is a pyproject.toml,
     the prepare_metadata_for_build_wheel hook is called.
     """
-    project_dir = _make_project(tmpdir, BACKEND_WITHOUT_PEP660, with_setup_py=False)
+    project_dir = _make_project(tmp_path, BACKEND_WITHOUT_PEP660, with_setup_py=False)
     result = script.pip(
         "install",
         "--no-index",
@@ -184,13 +192,15 @@ def test_install_no_pep660_setup_cfg_fallback(
 
 
 @pytest.mark.usefixtures("with_wheel")
-def test_wheel_editable_pep660_basic(tmpdir: Path, script: PipTestEnvironment) -> None:
+def test_wheel_editable_pep660_basic(
+    tmp_path: pathlib.Path, script: PipTestEnvironment
+) -> None:
     """
     Test 'pip wheel' of an editable pep 660 project.
     It must *not* call prepare_metadata_for_build_editable.
     """
-    project_dir = _make_project(tmpdir, BACKEND_WITH_PEP660, with_setup_py=False)
-    wheel_dir = tmpdir / "dist"
+    project_dir = _make_project(tmp_path, BACKEND_WITH_PEP660, with_setup_py=False)
+    wheel_dir = tmp_path / "dist"
     script.pip(
         "wheel",
         "--no-index",
@@ -204,21 +214,21 @@ def test_wheel_editable_pep660_basic(tmpdir: Path, script: PipTestEnvironment) -
     _assert_hook_not_called(project_dir, "build_editable")
     _assert_hook_called(project_dir, "prepare_metadata_for_build_wheel")
     _assert_hook_called(project_dir, "build_wheel")
-    assert len(os.listdir(str(wheel_dir))) == 1, "a wheel should have been created"
+    assert len(os.listdir(wheel_dir)) == 1, "a wheel should have been created"
 
 
 @pytest.mark.usefixtures("with_wheel")
 def test_download_editable_pep660_basic(
-    tmpdir: Path, script: PipTestEnvironment
+    tmp_path: pathlib.Path, script: PipTestEnvironment
 ) -> None:
     """
     Test 'pip download' of an editable pep 660 project.
     It must *not* call prepare_metadata_for_build_editable.
     """
-    project_dir = _make_project(tmpdir, BACKEND_WITH_PEP660, with_setup_py=False)
-    reqs_file = tmpdir / "requirements.txt"
-    reqs_file.write_text(f"-e {path_to_url(project_dir)}\n")
-    download_dir = tmpdir / "download"
+    project_dir = _make_project(tmp_path, BACKEND_WITH_PEP660, with_setup_py=False)
+    reqs_file = tmp_path / "requirements.txt"
+    reqs_file.write_text(f"-e {project_dir.as_uri()}\n")
+    download_dir = tmp_path / "download"
     script.pip(
         "download",
         "--no-index",
@@ -230,4 +240,4 @@ def test_download_editable_pep660_basic(
     )
     _assert_hook_not_called(project_dir, "prepare_metadata_for_build_editable")
     _assert_hook_called(project_dir, "prepare_metadata_for_build_wheel")
-    assert len(os.listdir(str(download_dir))) == 1, "a zip should have been created"
+    assert len(os.listdir(download_dir)) == 1, "a zip should have been created"
diff --git a/tests/functional/test_show.py b/tests/functional/test_show.py
index 6b434e51c56..aa4cd5b70ff 100644
--- a/tests/functional/test_show.py
+++ b/tests/functional/test_show.py
@@ -67,7 +67,7 @@ def test_show_with_files_from_legacy(
     # 'setup.py install' plus installed-files.txt, which we manually generate.
     source_dir = tmp_path.joinpath("unpacked-sdist")
     setuptools_record = tmp_path.joinpath("installed-record.txt")
-    untar_file(data.packages.joinpath("simple-1.0.tar.gz"), str(source_dir))
+    untar_file(str(data.packages.joinpath("simple-1.0.tar.gz")), str(source_dir))
     script.run(
         "python",
         "setup.py",
diff --git a/tests/functional/test_uninstall.py b/tests/functional/test_uninstall.py
index 431ea8dd5bf..11b1d587ca3 100644
--- a/tests/functional/test_uninstall.py
+++ b/tests/functional/test_uninstall.py
@@ -1,5 +1,6 @@
 import logging
 import os
+import pathlib
 import sys
 import textwrap
 from os.path import join, normpath
@@ -19,7 +20,6 @@
     need_svn,
 )
 from tests.lib.local_repos import local_checkout, local_repo
-from tests.lib.path import Path
 
 
 @pytest.mark.network
@@ -55,7 +55,7 @@ def test_basic_uninstall_distutils(script: PipTestEnvironment) -> None:
     """
         )
     )
-    result = script.run("python", pkg_path / "setup.py", "install")
+    result = script.run("python", str(pkg_path / "setup.py"), "install")
     result = script.pip("list", "--format=json")
     script.assert_installed(distutils_install="0.1")
     result = script.pip(
@@ -245,7 +245,7 @@ def test_uninstall_entry_point_colon_in_name(
     )
     script_name = script.bin_path.joinpath(console_scripts.split("=")[0].strip())
     if sys.platform == "win32":
-        script_name += ".exe"
+        script_name = script_name.with_suffix(".exe")
     script.pip("install", pkg_path)
     assert script_name.exists()
     script.assert_installed(ep_install="0.1")
@@ -272,7 +272,7 @@ def test_uninstall_gui_scripts(script: PipTestEnvironment) -> None:
     )
     script_name = script.bin_path.joinpath("test_")
     if sys.platform == "win32":
-        script_name += ".exe"
+        script_name = script_name.with_suffix(".exe")
     script.pip("install", pkg_path)
     assert script_name.exists()
     script.pip("uninstall", pkg_name, "-y")
@@ -299,7 +299,7 @@ def test_uninstall_console_scripts(script: PipTestEnvironment) -> None:
         [
             script.venv / "build",
             "cache",
-            Path("scratch") / "discover" / "discover.egg-info",
+            "scratch/discover/discover.egg-info",
         ],
     )
 
@@ -353,7 +353,10 @@ def test_uninstall_easy_installed_console_scripts(script: PipTestEnvironment) ->
 @pytest.mark.xfail
 @pytest.mark.network
 @need_svn
-def test_uninstall_editable_from_svn(script: PipTestEnvironment, tmpdir: Path) -> None:
+def test_uninstall_editable_from_svn(
+    script: PipTestEnvironment,
+    tmp_path: pathlib.Path,
+) -> None:
     """
     Test uninstalling an editable installation from svn.
     """
@@ -361,7 +364,7 @@ def test_uninstall_editable_from_svn(script: PipTestEnvironment, tmpdir: Path) -
         "install",
         "-e",
         "{checkout}#egg=initools".format(
-            checkout=local_checkout("svn+http://svn.colorstudy.com/INITools", tmpdir)
+            checkout=local_checkout("svn+http://svn.colorstudy.com/INITools", tmp_path)
         ),
     )
     result.assert_installed("INITools")
@@ -380,7 +383,7 @@ def test_uninstall_editable_from_svn(script: PipTestEnvironment, tmpdir: Path) -
 
 @pytest.mark.network
 def test_uninstall_editable_with_source_outside_venv(
-    script: PipTestEnvironment, tmpdir: Path
+    script: PipTestEnvironment, tmp_path: pathlib.Path
 ) -> None:
     """
     Test uninstalling editable install from existing source outside the venv.
@@ -390,7 +393,7 @@ def test_uninstall_editable_with_source_outside_venv(
         temp_pkg_dir = join(temp, "pip-test-package")
         _test_uninstall_editable_with_source_outside_venv(
             script,
-            tmpdir,
+            tmp_path,
             temp_pkg_dir,
         )
     finally:
@@ -399,13 +402,13 @@ def test_uninstall_editable_with_source_outside_venv(
 
 def _test_uninstall_editable_with_source_outside_venv(
     script: PipTestEnvironment,
-    tmpdir: Path,
+    tmp_path: pathlib.Path,
     temp_pkg_dir: str,
 ) -> None:
     result = script.run(
         "git",
         "clone",
-        local_repo("git+https://github.com/pypa/pip-test-package", tmpdir),
+        local_repo("git+https://github.com/pypa/pip-test-package", tmp_path),
         temp_pkg_dir,
         expect_stderr=True,
     )
@@ -422,14 +425,17 @@ def _test_uninstall_editable_with_source_outside_venv(
 @pytest.mark.xfail
 @pytest.mark.network
 @need_svn
-def test_uninstall_from_reqs_file(script: PipTestEnvironment, tmpdir: Path) -> None:
+def test_uninstall_from_reqs_file(
+    script: PipTestEnvironment,
+    tmp_path: pathlib.Path,
+) -> None:
     """
     Test uninstall from a requirements file.
 
     """
     local_svn_url = local_checkout(
         "svn+http://svn.colorstudy.com/INITools",
-        tmpdir,
+        tmp_path,
     )
     script.scratch_path.joinpath("test-req.txt").write_text(
         textwrap.dedent(
@@ -488,9 +494,11 @@ def test_uninstallpathset_no_paths(caplog: pytest.LogCaptureFixture) -> None:
 
 
 def test_uninstall_non_local_distutils(
-    caplog: pytest.LogCaptureFixture, monkeypatch: pytest.MonkeyPatch, tmpdir: Path
+    caplog: pytest.LogCaptureFixture,
+    monkeypatch: pytest.MonkeyPatch,
+    tmp_path: pathlib.Path,
 ) -> None:
-    einfo = tmpdir.joinpath("thing-1.0.egg-info")
+    einfo = tmp_path.joinpath("thing-1.0.egg-info")
     with open(einfo, "wb"):
         pass
 
@@ -583,7 +591,7 @@ def test_uninstall_without_record_fails(
 
 @pytest.mark.skipif("sys.platform == 'win32'")
 def test_uninstall_with_symlink(
-    script: PipTestEnvironment, data: TestData, tmpdir: Path
+    script: PipTestEnvironment, data: TestData, tmp_path: pathlib.Path
 ) -> None:
     """
     Test uninstalling a wheel, with an additional symlink
@@ -591,7 +599,7 @@ def test_uninstall_with_symlink(
     """
     package = data.packages.joinpath("simple.dist-0.1-py2.py3-none-any.whl")
     script.pip("install", package, "--no-index")
-    symlink_target = tmpdir / "target"
+    symlink_target = tmp_path / "target"
     symlink_target.mkdir()
     symlink_source = script.site_packages / "symlink"
     (script.base_path / symlink_source).symlink_to(symlink_target)
diff --git a/tests/functional/test_vcs_bazaar.py b/tests/functional/test_vcs_bazaar.py
index 06f9cbc8107..e68a637512f 100644
--- a/tests/functional/test_vcs_bazaar.py
+++ b/tests/functional/test_vcs_bazaar.py
@@ -3,6 +3,7 @@
 """
 
 import os
+import pathlib
 import sys
 
 import pytest
@@ -10,7 +11,6 @@
 from pip._internal.vcs.bazaar import Bazaar
 from pip._internal.vcs.versioncontrol import RemoteNotFoundError
 from tests.lib import PipTestEnvironment, is_bzr_installed, need_bzr
-from tests.lib.path import Path
 
 
 @pytest.mark.skipif(
@@ -23,11 +23,14 @@ def test_ensure_bzr_available() -> None:
 
 
 @need_bzr
-def test_get_remote_url__no_remote(script: PipTestEnvironment, tmpdir: Path) -> None:
-    repo_dir = tmpdir / "temp-repo"
+def test_get_remote_url__no_remote(
+    script: PipTestEnvironment,
+    tmp_path: pathlib.Path,
+) -> None:
+    repo_dir = tmp_path / "temp-repo"
     repo_dir.mkdir()
 
-    script.run("bzr", "init", repo_dir)
+    script.run("bzr", "init", str(repo_dir))
 
     with pytest.raises(RemoteNotFoundError):
-        Bazaar().get_remote_url(repo_dir)
+        Bazaar().get_remote_url(str(repo_dir))
diff --git a/tests/functional/test_vcs_git.py b/tests/functional/test_vcs_git.py
index b535d2eab87..c5dc3800ee1 100644
--- a/tests/functional/test_vcs_git.py
+++ b/tests/functional/test_vcs_git.py
@@ -12,13 +12,7 @@
 from pip._internal.utils.misc import HiddenText
 from pip._internal.vcs import vcs
 from pip._internal.vcs.git import Git, RemoteNotFoundError
-from tests.lib import (
-    PipTestEnvironment,
-    _create_test_package,
-    _git_commit,
-    _test_path_to_file_url,
-)
-from tests.lib.path import Path
+from tests.lib import PipTestEnvironment, _create_test_package, _git_commit
 
 
 def test_get_backend_for_scheme() -> None:
@@ -66,11 +60,11 @@ def check_rev(repo_dir: str, rev: str, expected: Tuple[Optional[str], bool]) ->
     assert Git.get_revision_sha(repo_dir, rev) == expected
 
 
-def test_git_dir_ignored(tmpdir: Path) -> None:
+def test_git_dir_ignored(tmp_path: pathlib.Path) -> None:
     """
     Test that a GIT_DIR environment variable is ignored.
     """
-    repo_path = tmpdir / "test-repo"
+    repo_path = tmp_path / "test-repo"
     repo_path.mkdir()
     repo_dir = str(repo_path)
 
@@ -80,11 +74,11 @@ def test_git_dir_ignored(tmpdir: Path) -> None:
     assert os.listdir(repo_dir) == [".git"]
 
 
-def test_git_work_tree_ignored(tmpdir: Path) -> None:
+def test_git_work_tree_ignored(tmp_path: pathlib.Path) -> None:
     """
     Test that a GIT_WORK_TREE environment variable is ignored.
     """
-    repo_path = tmpdir / "test-repo"
+    repo_path = tmp_path / "test-repo"
     repo_path.mkdir()
     repo_dir = str(repo_path)
 
@@ -96,27 +90,29 @@ def test_git_work_tree_ignored(tmpdir: Path) -> None:
     Git.run_command(["status", repo_dir], extra_environ=env, cwd=repo_dir)
 
 
-def test_get_remote_url(script: PipTestEnvironment, tmpdir: Path) -> None:
-    source_path = tmpdir / "source"
+def test_get_remote_url(script: PipTestEnvironment, tmp_path: pathlib.Path) -> None:
+    source_path = tmp_path / "source"
     source_path.mkdir()
-    source_url = _test_path_to_file_url(source_path)
+    source_url = source_path.as_uri()
 
     source_dir = str(source_path)
     script.run("git", "init", cwd=source_dir)
     do_commit(script, source_dir)
 
-    repo_dir = str(tmpdir / "repo")
+    repo_dir = str(tmp_path / "repo")
     script.run("git", "clone", source_url, repo_dir)
 
     remote_url = Git.get_remote_url(repo_dir)
     assert remote_url == source_url
 
 
-def test_get_remote_url__no_remote(script: PipTestEnvironment, tmpdir: Path) -> None:
+def test_get_remote_url__no_remote(
+    script: PipTestEnvironment, tmp_path: pathlib.Path
+) -> None:
     """
     Test a repo with no remote.
     """
-    repo_path = tmpdir / "temp-repo"
+    repo_path = tmp_path / "temp-repo"
     repo_path.mkdir()
     repo_dir = str(repo_path)
 
@@ -145,13 +141,13 @@ def test_get_current_branch(script: PipTestEnvironment) -> None:
 
 
 def test_get_current_branch__branch_and_tag_same_name(
-    script: PipTestEnvironment, tmpdir: Path
+    script: PipTestEnvironment, tmp_path: pathlib.Path
 ) -> None:
     """
     Check calling get_current_branch() from a branch or tag when the branch
     and tag have the same name.
     """
-    repo_dir = str(tmpdir)
+    repo_dir = str(tmp_path)
     script.run("git", "init", cwd=repo_dir)
     do_commit(script, repo_dir)
     checkout_new_branch(script, repo_dir, "dev")
@@ -229,23 +225,25 @@ def test_is_commit_id_equal(script: PipTestEnvironment) -> None:
     script.run("git", "branch", "branch0.1", cwd=version_pkg_path)
     commit = script.run("git", "rev-parse", "HEAD", cwd=version_pkg_path).stdout.strip()
 
-    assert Git.is_commit_id_equal(version_pkg_path, commit)
-    assert not Git.is_commit_id_equal(version_pkg_path, commit[:7])
-    assert not Git.is_commit_id_equal(version_pkg_path, "branch0.1")
-    assert not Git.is_commit_id_equal(version_pkg_path, "abc123")
+    assert Git.is_commit_id_equal(str(version_pkg_path), commit)
+    assert not Git.is_commit_id_equal(str(version_pkg_path), commit[:7])
+    assert not Git.is_commit_id_equal(str(version_pkg_path), "branch0.1")
+    assert not Git.is_commit_id_equal(str(version_pkg_path), "abc123")
     # Also check passing a None value.
-    assert not Git.is_commit_id_equal(version_pkg_path, None)
+    assert not Git.is_commit_id_equal(str(version_pkg_path), None)
 
 
 def test_is_immutable_rev_checkout(script: PipTestEnvironment) -> None:
     version_pkg_path = _create_test_package(script)
     commit = script.run("git", "rev-parse", "HEAD", cwd=version_pkg_path).stdout.strip()
     assert Git().is_immutable_rev_checkout(
-        "git+https://g.c/o/r@" + commit, version_pkg_path
+        "git+https://g.c/o/r@" + commit, str(version_pkg_path)
+    )
+    assert not Git().is_immutable_rev_checkout(
+        "git+https://g.c/o/r", str(version_pkg_path)
     )
-    assert not Git().is_immutable_rev_checkout("git+https://g.c/o/r", version_pkg_path)
     assert not Git().is_immutable_rev_checkout(
-        "git+https://g.c/o/r@master", version_pkg_path
+        "git+https://g.c/o/r@master", str(version_pkg_path)
     )
 
 
@@ -254,11 +252,11 @@ def test_get_repository_root(script: PipTestEnvironment) -> None:
     tests_path = version_pkg_path.joinpath("tests")
     tests_path.mkdir()
 
-    root1 = Git.get_repository_root(version_pkg_path)
+    root1 = Git.get_repository_root(str(version_pkg_path))
     assert root1 is not None
     assert os.path.normcase(root1) == os.path.normcase(version_pkg_path)
 
-    root2 = Git.get_repository_root(version_pkg_path.joinpath("tests"))
+    root2 = Git.get_repository_root(str(version_pkg_path.joinpath("tests")))
     assert root2 is not None
     assert os.path.normcase(root2) == os.path.normcase(version_pkg_path)
 
diff --git a/tests/functional/test_vcs_mercurial.py b/tests/functional/test_vcs_mercurial.py
index 3ac7ac3d1fc..47b26d375c8 100644
--- a/tests/functional/test_vcs_mercurial.py
+++ b/tests/functional/test_vcs_mercurial.py
@@ -10,10 +10,10 @@ def test_get_repository_root(script: PipTestEnvironment) -> None:
     tests_path = version_pkg_path.joinpath("tests")
     tests_path.mkdir()
 
-    root1 = Mercurial.get_repository_root(version_pkg_path)
+    root1 = Mercurial.get_repository_root(str(version_pkg_path))
     assert root1 is not None
     assert os.path.normcase(root1) == os.path.normcase(version_pkg_path)
 
-    root2 = Mercurial.get_repository_root(version_pkg_path.joinpath("tests"))
+    root2 = Mercurial.get_repository_root(str(version_pkg_path.joinpath("tests")))
     assert root2 is not None
     assert os.path.normcase(root2) == os.path.normcase(version_pkg_path)
diff --git a/tests/functional/test_vcs_subversion.py b/tests/functional/test_vcs_subversion.py
index 91627af8688..06eed0b58d6 100644
--- a/tests/functional/test_vcs_subversion.py
+++ b/tests/functional/test_vcs_subversion.py
@@ -1,14 +1,18 @@
+import pathlib
+
 import pytest
 
 from pip._internal.vcs.subversion import Subversion
 from pip._internal.vcs.versioncontrol import RemoteNotFoundError
 from tests.lib import PipTestEnvironment, _create_svn_repo, need_svn
-from tests.lib.path import Path
 
 
 @need_svn
-def test_get_remote_url__no_remote(script: PipTestEnvironment, tmpdir: Path) -> None:
-    repo_path = tmpdir / "temp-repo"
+def test_get_remote_url__no_remote(
+    script: PipTestEnvironment,
+    tmp_path: pathlib.Path,
+) -> None:
+    repo_path = tmp_path / "temp-repo"
     repo_path.mkdir()
     repo_dir = str(repo_path)
 
@@ -20,9 +24,9 @@ def test_get_remote_url__no_remote(script: PipTestEnvironment, tmpdir: Path) ->
 
 @need_svn
 def test_get_remote_url__no_remote_with_setup(
-    script: PipTestEnvironment, tmpdir: Path
+    script: PipTestEnvironment, tmp_path: pathlib.Path
 ) -> None:
-    repo_path = tmpdir / "temp-repo"
+    repo_path = tmp_path / "temp-repo"
     repo_path.mkdir()
     setup = repo_path / "setup.py"
     setup.touch()
diff --git a/tests/functional/test_warning.py b/tests/functional/test_warning.py
index a7018944873..e04f98708ff 100644
--- a/tests/functional/test_warning.py
+++ b/tests/functional/test_warning.py
@@ -1,15 +1,15 @@
+import pathlib
 import sys
 import textwrap
 
 import pytest
 
 from tests.lib import PipTestEnvironment
-from tests.lib.path import Path
 
 
 @pytest.fixture
-def warnings_demo(tmpdir: Path) -> Path:
-    demo = tmpdir.joinpath("warnings_demo.py")
+def warnings_demo(tmp_path: pathlib.Path) -> pathlib.Path:
+    demo = tmp_path.joinpath("warnings_demo.py")
     demo.write_text(
         textwrap.dedent(
             """
@@ -27,18 +27,18 @@ def warnings_demo(tmpdir: Path) -> Path:
 
 
 def test_deprecation_warnings_are_correct(
-    script: PipTestEnvironment, warnings_demo: Path
+    script: PipTestEnvironment, warnings_demo: pathlib.Path
 ) -> None:
-    result = script.run("python", warnings_demo, expect_stderr=True)
+    result = script.run("python", str(warnings_demo), expect_stderr=True)
     expected = "WARNING:pip._internal.deprecations:DEPRECATION: deprecated!\n"
     assert result.stderr == expected
 
 
 def test_deprecation_warnings_can_be_silenced(
-    script: PipTestEnvironment, warnings_demo: Path
+    script: PipTestEnvironment, warnings_demo: pathlib.Path
 ) -> None:
     script.environ["PYTHONWARNINGS"] = "ignore"
-    result = script.run("python", warnings_demo)
+    result = script.run("python", str(warnings_demo))
     assert result.stderr == ""
 
 
diff --git a/tests/functional/test_wheel.py b/tests/functional/test_wheel.py
index dedf22ba8cc..66bdd8fe774 100644
--- a/tests/functional/test_wheel.py
+++ b/tests/functional/test_wheel.py
@@ -1,5 +1,6 @@
 """'pip wheel' tests"""
 import os
+import pathlib
 import re
 import sys
 
@@ -8,12 +9,11 @@
 from pip._internal.cli.status_codes import ERROR
 from tests.lib import pyversion  # noqa: F401
 from tests.lib import PipTestEnvironment, TestData
-from tests.lib.path import Path
 
 pytestmark = pytest.mark.usefixtures("with_wheel")
 
 
-def add_files_to_dist_directory(folder: Path) -> None:
+def add_files_to_dist_directory(folder: pathlib.Path) -> None:
     (folder / "dist").mkdir(parents=True)
     (folder / "dist" / "a_name-0.0.1.tar.gz").write_text("hello")
     # Not adding a wheel file since that confuses setuptools' backend.
@@ -154,9 +154,9 @@ def test_pip_wheel_builds_when_no_binary_set(
 
 @pytest.mark.skipif("sys.platform == 'win32'")
 def test_pip_wheel_readonly_cache(
-    script: PipTestEnvironment, data: TestData, tmpdir: Path
+    script: PipTestEnvironment, data: TestData, tmp_path: pathlib.Path
 ) -> None:
-    cache_dir = tmpdir / "cache"
+    cache_dir = tmp_path / "cache"
     cache_dir.mkdir()
     os.chmod(cache_dir, 0o400)  # read-only cache
     # Check that the wheel package is ignored
@@ -204,7 +204,7 @@ def test_pip_wheel_builds_editable(script: PipTestEnvironment, data: TestData) -
 
 @pytest.mark.network
 def test_pip_wheel_git_editable_keeps_clone(
-    script: PipTestEnvironment, tmpdir: Path
+    script: PipTestEnvironment, tmp_path: pathlib.Path
 ) -> None:
     """
     Test that `pip wheel -e giturl` preserves a git clone in src.
@@ -215,24 +215,24 @@ def test_pip_wheel_git_editable_keeps_clone(
         "-e",
         "git+https://github.com/pypa/pip-test-package#egg=pip-test-package",
         "--src",
-        tmpdir / "src",
+        tmp_path / "src",
         "--wheel-dir",
-        tmpdir,
+        tmp_path,
     )
-    assert (tmpdir / "src" / "pip-test-package").exists()
-    assert (tmpdir / "src" / "pip-test-package" / ".git").exists()
+    assert (tmp_path / "src" / "pip-test-package").exists()
+    assert (tmp_path / "src" / "pip-test-package" / ".git").exists()
 
 
 def test_pip_wheel_builds_editable_does_not_create_zip(
-    script: PipTestEnvironment, data: TestData, tmpdir: Path
+    script: PipTestEnvironment, data: TestData, tmp_path: pathlib.Path
 ) -> None:
     """
     Test 'pip wheel' of editables does not create zip files
     (regression test for issue #9122)
     """
-    wheel_dir = tmpdir / "wheel_dir"
+    wheel_dir = tmp_path / "wheel_dir"
     wheel_dir.mkdir()
-    editable_path = os.path.join(data.src, "simplewheel-1.0")
+    editable_path = data.src.joinpath("simplewheel-1.0")
     script.pip("wheel", "--no-deps", "-e", editable_path, "-w", wheel_dir)
     wheels = os.listdir(wheel_dir)
     assert len(wheels) == 1
@@ -289,7 +289,7 @@ def test_wheel_package_with_latin1_setup(
 
 
 def test_pip_wheel_with_pep518_build_reqs(
-    script: PipTestEnvironment, data: TestData, common_wheels: Path
+    script: PipTestEnvironment, data: TestData, common_wheels: pathlib.Path
 ) -> None:
     result = script.pip(
         "wheel",
@@ -327,13 +327,17 @@ def test_pip_wheel_with_pep518_build_reqs_no_isolation(
 
 
 def test_pip_wheel_with_user_set_in_config(
-    script: PipTestEnvironment, data: TestData, common_wheels: Path
+    script: PipTestEnvironment, data: TestData, common_wheels: pathlib.Path
 ) -> None:
     config_file = script.scratch_path / "pip.conf"
     script.environ["PIP_CONFIG_FILE"] = str(config_file)
     config_file.write_text("[install]\nuser = true")
     result = script.pip(
-        "wheel", data.src / "withpyproject", "--no-index", "-f", common_wheels
+        "wheel",
+        data.src / "withpyproject",
+        "--no-index",
+        "-f",
+        common_wheels,
     )
     assert "Successfully built withpyproject" in result.stdout, result.stdout
 
@@ -343,7 +347,7 @@ def test_pip_wheel_with_user_set_in_config(
     reason="The empty extension module does not work on Win",
 )
 def test_pip_wheel_ext_module_with_tmpdir_inside(
-    script: PipTestEnvironment, data: TestData, common_wheels: Path
+    script: PipTestEnvironment, data: TestData, common_wheels: pathlib.Path
 ) -> None:
     tmpdir = data.src / "extension/tmp"
     tmpdir.mkdir()
@@ -354,7 +358,11 @@ def test_pip_wheel_ext_module_with_tmpdir_inside(
     script.environ["CC"] = script.environ["LDSHARED"] = "true"
 
     result = script.pip(
-        "wheel", data.src / "extension", "--no-index", "-f", common_wheels
+        "wheel",
+        data.src / "extension",
+        "--no-index",
+        "-f",
+        common_wheels,
     )
     assert "Successfully built extension" in result.stdout, result.stdout
 
diff --git a/tests/lib/__init__.py b/tests/lib/__init__.py
index c8d68fea9b0..84d97aceb61 100644
--- a/tests/lib/__init__.py
+++ b/tests/lib/__init__.py
@@ -16,6 +16,7 @@
     TYPE_CHECKING,
     Any,
     Callable,
+    Collection,
     Dict,
     Iterator,
     List,
@@ -38,7 +39,6 @@
 from pip._internal.models.target_python import TargetPython
 from pip._internal.network.session import PipSession
 from pip._internal.utils.deprecation import DEPRECATION_MSG_PREFIX
-from tests.lib.path import Path, curdir
 from tests.lib.venv import VirtualEnvironment
 from tests.lib.wheel import make_wheel
 
@@ -50,8 +50,8 @@
 else:
     ResolverVariant = str
 
-DATA_DIR = Path(__file__).parent.parent.joinpath("data").resolve()
-SRC_DIR = Path(__file__).resolve().parent.parent.parent
+DATA_DIR = pathlib.Path(__file__).parent.parent.joinpath("data").resolve()
+SRC_DIR = pathlib.Path(__file__).resolve().parent.parent.parent
 
 pyversion = get_major_minor_version()
 
@@ -65,33 +65,6 @@ def assert_paths_equal(actual: str, expected: str) -> None:
     assert os.path.normpath(actual) == os.path.normpath(expected)
 
 
-def path_to_url(path: str) -> str:
-    """
-    Convert a path to URI. The path will be made absolute and
-    will not have quoted path parts.
-    (adapted from pip.util)
-    """
-    path = os.path.normpath(os.path.abspath(path))
-    drive, path = os.path.splitdrive(path)
-    filepath = path.split(os.path.sep)
-    url = "/".join(filepath)
-    if drive:
-        # Note: match urllib.request.pathname2url's
-        # behavior: uppercase the drive letter.
-        return "file:///" + drive.upper() + url
-    return "file://" + url
-
-
-def _test_path_to_file_url(path: Path) -> str:
-    """
-    Convert a test Path to a "file://" URL.
-
-    Args:
-      path: a tests.lib.path.Path object.
-    """
-    return "file://" + path.resolve().replace("\\", "/")
-
-
 def create_file(path: str, contents: Optional[str] = None) -> None:
     """Create a file on the path, with the given contents"""
     from pip._internal.utils.misc import ensure_dir
@@ -178,12 +151,16 @@ class TestData:
 
     __test__ = False
 
-    def __init__(self, root: str, source: Optional[Path] = None) -> None:
+    def __init__(
+        self,
+        root: pathlib.Path,
+        source: Optional[pathlib.Path] = None,
+    ) -> None:
         self.source = source or DATA_DIR
-        self.root = Path(root).resolve()
+        self.root = root.resolve()
 
     @classmethod
-    def copy(cls, root: str) -> "TestData":
+    def copy(cls, root: pathlib.Path) -> "TestData":
         obj = cls(root)
         obj.reset()
         return obj
@@ -196,51 +173,51 @@ def reset(self) -> None:
         shutil.copytree(self.source, self.root, symlinks=True)
 
     @property
-    def packages(self) -> Path:
+    def packages(self) -> pathlib.Path:
         return self.root.joinpath("packages")
 
     @property
-    def packages2(self) -> Path:
+    def packages2(self) -> pathlib.Path:
         return self.root.joinpath("packages2")
 
     @property
-    def packages3(self) -> Path:
+    def packages3(self) -> pathlib.Path:
         return self.root.joinpath("packages3")
 
     @property
-    def src(self) -> Path:
+    def src(self) -> pathlib.Path:
         return self.root.joinpath("src")
 
     @property
-    def indexes(self) -> Path:
+    def indexes(self) -> pathlib.Path:
         return self.root.joinpath("indexes")
 
     @property
-    def reqfiles(self) -> Path:
+    def reqfiles(self) -> pathlib.Path:
         return self.root.joinpath("reqfiles")
 
     @property
-    def completion_paths(self) -> Path:
+    def completion_paths(self) -> pathlib.Path:
         return self.root.joinpath("completion_paths")
 
     @property
     def find_links(self) -> str:
-        return path_to_url(self.packages)
+        return self.packages.as_uri()
 
     @property
     def find_links2(self) -> str:
-        return path_to_url(self.packages2)
+        return self.packages2.as_uri()
 
     @property
     def find_links3(self) -> str:
-        return path_to_url(self.packages3)
+        return self.packages3.as_uri()
 
     @property
     def backends(self) -> str:
-        return path_to_url(self.root.joinpath("backends"))
+        return self.root.joinpath("backends").as_uri()
 
     def index_url(self, index: str = "simple") -> str:
-        return path_to_url(self.root.joinpath("indexes", index))
+        return self.root.joinpath("indexes", index).as_uri()
 
 
 class TestFailure(AssertionError):
@@ -248,7 +225,8 @@ class TestFailure(AssertionError):
     An "assertion" failed during testing.
     """
 
-    pass
+
+StrPath = Union[str, pathlib.Path]
 
 
 class TestPipResult:
@@ -355,8 +333,8 @@ def assert_installed(
             maybe = "" if without_egg_link else "not "
             raise TestFailure(f"{pth_file} unexpectedly {maybe}updated by install")
 
-        if (pkg_dir in self.files_created) == (curdir in without_files):
-            maybe = "not " if curdir in without_files else ""
+        if (pkg_dir in self.files_created) == (os.curdir in without_files):
+            maybe = "not " if os.curdir in without_files else ""
             files = sorted(self.files_created)
             raise TestFailure(
                 textwrap.dedent(
@@ -382,17 +360,25 @@ def assert_installed(
                     f"Package directory {pkg_dir!r} has unexpected content {f}"
                 )
 
-    def did_create(self, path: str, message: Optional[str] = None) -> None:
-        assert str(path) in self.files_created, _one_or_both(message, self)
+    @property
+    def _paths_created(self) -> Collection[pathlib.Path]:
+        return {pathlib.Path(s) for s in self.files_created}
+
+    @property
+    def _paths_updated(self) -> Collection[pathlib.Path]:
+        return {pathlib.Path(s) for s in self.files_updated}
+
+    def did_create(self, path: StrPath, message: Optional[str] = None) -> None:
+        assert pathlib.Path(path) in self._paths_created, _one_or_both(message, self)
 
-    def did_not_create(self, path: str, message: Optional[str] = None) -> None:
-        assert str(path) not in self.files_created, _one_or_both(message, self)
+    def did_not_create(self, p: StrPath, message: Optional[str] = None) -> None:
+        assert pathlib.Path(p) not in self._paths_created, _one_or_both(message, self)
 
-    def did_update(self, path: str, message: Optional[str] = None) -> None:
-        assert str(path) in self.files_updated, _one_or_both(message, self)
+    def did_update(self, path: StrPath, message: Optional[str] = None) -> None:
+        assert pathlib.Path(path) in self._paths_updated, _one_or_both(message, self)
 
-    def did_not_update(self, path: str, message: Optional[str] = None) -> None:
-        assert str(path) not in self.files_updated, _one_or_both(message, self)
+    def did_not_update(self, p: StrPath, message: Optional[str] = None) -> None:
+        assert pathlib.Path(p) not in self._paths_updated, _one_or_both(message, self)
 
 
 def _one_or_both(a: Optional[str], b: Any) -> str:
@@ -487,15 +473,12 @@ class PipTestEnvironment(TestFileEnvironment):
 
     def __init__(
         self,
-        base_path: str,
+        base_path: pathlib.Path,
         *args: Any,
         virtualenv: VirtualEnvironment,
         pip_expect_warning: bool = False,
         **kwargs: Any,
     ) -> None:
-        # Make our base_path a test.lib.path.Path object
-        base_path = Path(base_path)
-
         # Store paths related to the virtual environment
         self.venv_path = virtualenv.location
         self.lib_path = virtualenv.lib
@@ -511,7 +494,7 @@ def __init__(
             site.USER_SITE[len(site.USER_BASE) + 1 :],
         )
         if sys.platform == "win32":
-            scripts_base = Path(os.path.normpath(self.user_site_path.joinpath("..")))
+            scripts_base = self.user_site_path.joinpath("..")
             self.user_bin_path = scripts_base.joinpath("Scripts")
         else:
             self.user_bin_path = self.user_base_path.joinpath(
@@ -527,8 +510,8 @@ def __init__(
 
         # Setup our environment
         environ = kwargs.setdefault("environ", os.environ.copy())
-        environ["PATH"] = Path.pathsep.join(
-            [self.bin_path] + [environ.get("PATH", [])],
+        environ["PATH"] = os.pathsep.join(
+            [str(self.bin_path), environ.get("PATH", "")],
         )
         environ["PYTHONUSERBASE"] = self.user_base_path
         # Writing bytecode can mess up updated file detection
@@ -556,13 +539,13 @@ def __init__(
             "scratch",
         ]:
             real_name = f"{name}_path"
-            relative_path = Path(
+            relative_path = pathlib.Path(
                 os.path.relpath(getattr(self, real_name), self.base_path)
             )
             setattr(self, name, relative_path)
 
         # Make sure temp_path is a Path object
-        self.temp_path: Path = Path(self.temp_path)
+        self.temp_path: pathlib.Path = pathlib.Path(self.temp_path)
         # Ensure the tmp dir exists, things break horribly if it doesn't
         self.temp_path.mkdir()
 
@@ -676,7 +659,12 @@ def run(
 
         return TestPipResult(result, verbose=self.verbose)
 
-    def pip(self, *args: str, use_module: bool = True, **kwargs: Any) -> TestPipResult:
+    def pip(
+        self,
+        *args: Union[str, pathlib.Path],
+        use_module: bool = True,
+        **kwargs: Any,
+    ) -> TestPipResult:
         __tracebackhide__ = True
         if self.pip_expect_warning:
             kwargs["allow_stderr_warning"] = True
@@ -685,14 +673,18 @@ def pip(self, *args: str, use_module: bool = True, **kwargs: Any) -> TestPipResu
             args = ("-m", "pip") + args
         else:
             exe = "pip"
-        return self.run(exe, *args, **kwargs)
+        return self.run(exe, *(os.fspath(a) for a in args), **kwargs)
 
-    def pip_install_local(self, *args: str, **kwargs: Any) -> TestPipResult:
+    def pip_install_local(
+        self,
+        *args: Union[str, pathlib.Path],
+        **kwargs: Any,
+    ) -> TestPipResult:
         return self.pip(
             "install",
             "--no-index",
             "--find-links",
-            path_to_url(os.path.join(DATA_DIR, "packages")),
+            pathlib.Path(DATA_DIR, "packages").as_uri(),
             *args,
             **kwargs,
         )
@@ -813,7 +805,9 @@ def assert_all_changes(
 
 
 def _create_main_file(
-    dir_path: Path, name: Optional[str] = None, output: Optional[str] = None
+    dir_path: pathlib.Path,
+    name: Optional[str] = None,
+    output: Optional[str] = None,
 ) -> None:
     """
     Create a module with a main() function that prints the given output.
@@ -834,7 +828,7 @@ def main():
 
 def _git_commit(
     env_or_script: PipTestEnvironment,
-    repo_dir: str,
+    repo_dir: Union[str, pathlib.Path],
     message: Optional[str] = None,
     allow_empty: bool = False,
     stage_modified: bool = False,
@@ -871,8 +865,10 @@ def _git_commit(
 
 
 def _vcs_add(
-    script: PipTestEnvironment, version_pkg_path: Path, vcs: str = "git"
-) -> Path:
+    script: PipTestEnvironment,
+    version_pkg_path: pathlib.Path,
+    vcs: str = "git",
+) -> pathlib.Path:
     if vcs == "git":
         script.run("git", "init", cwd=version_pkg_path)
         script.run("git", "add", ".", cwd=version_pkg_path)
@@ -895,10 +891,7 @@ def _vcs_add(
         script.run(
             "svn", "checkout", repo_url, "pip-test-package", cwd=script.scratch_path
         )
-        checkout_path: str = script.scratch_path / "pip-test-package"
-
-        # svn internally stores windows drives as uppercase; we'll match that.
-        checkout_path = Path(checkout_path.replace("c:", "C:"))
+        checkout_path = script.scratch_path / "pip-test-package"
 
         version_pkg_path = checkout_path
     elif vcs == "bazaar":
@@ -924,7 +917,7 @@ def _vcs_add(
 
 def _create_test_package_with_subdirectory(
     script: PipTestEnvironment, subdirectory: str
-) -> Path:
+) -> pathlib.Path:
     script.scratch_path.joinpath("version_pkg").mkdir()
     version_pkg_path = script.scratch_path / "version_pkg"
     _create_main_file(version_pkg_path, name="version_pkg", output="0.1")
@@ -973,7 +966,7 @@ def _create_test_package_with_subdirectory(
 
 def _create_test_package_with_srcdir(
     script: PipTestEnvironment, name: str = "version_pkg", vcs: str = "git"
-) -> Path:
+) -> pathlib.Path:
     script.scratch_path.joinpath(name).mkdir()
     version_pkg_path = script.scratch_path / name
     subdir_path = version_pkg_path.joinpath("subdir")
@@ -1003,7 +996,7 @@ def _create_test_package_with_srcdir(
 
 def _create_test_package(
     script: PipTestEnvironment, name: str = "version_pkg", vcs: str = "git"
-) -> Path:
+) -> pathlib.Path:
     script.scratch_path.joinpath(name).mkdir()
     version_pkg_path = script.scratch_path / name
     _create_main_file(version_pkg_path, name=name, output="0.1")
@@ -1026,13 +1019,16 @@ def _create_test_package(
     return _vcs_add(script, version_pkg_path, vcs)
 
 
-def _create_svn_repo(script: PipTestEnvironment, version_pkg_path: str) -> str:
-    repo_url = path_to_url(script.scratch_path / "pip-test-package-repo" / "trunk")
+def _create_svn_repo(
+    script: PipTestEnvironment,
+    version_pkg_path: Union[pathlib.Path, str],
+) -> str:
+    repo_url = script.scratch_path.joinpath("pip-test-package-repo", "trunk").as_uri()
     script.run("svnadmin", "create", "pip-test-package-repo", cwd=script.scratch_path)
     script.run(
         "svn",
         "import",
-        version_pkg_path,
+        str(version_pkg_path),
         repo_url,
         "-m",
         "Initial import of pip-test-package",
@@ -1042,7 +1038,7 @@ def _create_svn_repo(script: PipTestEnvironment, version_pkg_path: str) -> str:
 
 
 def _change_test_package_version(
-    script: PipTestEnvironment, version_pkg_path: Path
+    script: PipTestEnvironment, version_pkg_path: pathlib.Path
 ) -> None:
     _create_main_file(
         version_pkg_path, name="version_pkg", output="some different version"
@@ -1052,15 +1048,15 @@ def _change_test_package_version(
 
 
 @contextmanager
-def requirements_file(contents: str, tmpdir: Path) -> Iterator[Path]:
+def requirements_file(contents: str, tmp_path: pathlib.Path) -> Iterator[pathlib.Path]:
     """Return a Path to a requirements file of given contents.
 
     As long as the context manager is open, the requirements file will exist.
 
-    :param tmpdir: A Path to the folder in which to create the file
+    :param tmp_path: A Path to the folder in which to create the file
 
     """
-    path = tmpdir / "reqs.txt"
+    path = tmp_path / "reqs.txt"
     path.write_text(contents)
     yield path
     path.unlink()
@@ -1068,7 +1064,7 @@ def requirements_file(contents: str, tmpdir: Path) -> Iterator[Path]:
 
 def create_test_package_with_setup(
     script: PipTestEnvironment, **setup_kwargs: Any
-) -> Path:
+) -> pathlib.Path:
     assert "name" in setup_kwargs, setup_kwargs
     pkg_path = script.scratch_path / setup_kwargs["name"]
     pkg_path.mkdir()
@@ -1128,7 +1124,7 @@ def create_basic_wheel_for_package(
     extras: Dict[str, List[str]] = None,
     requires_python: Optional[str] = None,
     extra_files: Optional[Dict[str, Union[bytes, str]]] = None,
-) -> Path:
+) -> pathlib.Path:
     if depends is None:
         depends = []
     if extras is None:
@@ -1188,7 +1184,7 @@ def create_basic_sdist_for_package(
     *,
     fails_egg_info: bool = False,
     fails_bdist_wheel: bool = False,
-) -> Path:
+) -> pathlib.Path:
     files = {
         "setup.py": f"""\
             import sys
@@ -1227,7 +1223,7 @@ def create_basic_sdist_for_package(
 
     retval = script.scratch_path / archive_name
     generated = shutil.make_archive(
-        retval,
+        str(retval),
         "gztar",
         root_dir=script.temp_path,
         base_dir=os.curdir,
diff --git a/tests/lib/direct_url.py b/tests/lib/direct_url.py
index ec0a32b4d66..98d7c61f661 100644
--- a/tests/lib/direct_url.py
+++ b/tests/lib/direct_url.py
@@ -1,12 +1,15 @@
+import pathlib
 import re
 from typing import Optional
 
 from pip._internal.models.direct_url import DIRECT_URL_METADATA_NAME, DirectUrl
 from tests.lib import TestPipResult
-from tests.lib.path import Path
 
 
-def get_created_direct_url_path(result: TestPipResult, pkg: str) -> Optional[Path]:
+def get_created_direct_url_path(
+    result: TestPipResult,
+    pkg: str,
+) -> Optional[pathlib.Path]:
     direct_url_metadata_re = re.compile(
         pkg + r"-[\d\.]+\.dist-info." + DIRECT_URL_METADATA_NAME + r"$"
     )
diff --git a/tests/lib/git_submodule_helpers.py b/tests/lib/git_submodule_helpers.py
index 32a3c000287..5f8811f4c12 100644
--- a/tests/lib/git_submodule_helpers.py
+++ b/tests/lib/git_submodule_helpers.py
@@ -1,11 +1,11 @@
+import pathlib
 import textwrap
 from typing import Tuple
 
 from tests.lib import PipTestEnvironment, _create_main_file, _git_commit
-from tests.lib.path import Path
 
 
-def _create_test_package_submodule(env: PipTestEnvironment) -> Path:
+def _create_test_package_submodule(env: PipTestEnvironment) -> pathlib.Path:
     env.scratch_path.joinpath("version_pkg_submodule").mkdir()
     submodule_path = env.scratch_path / "version_pkg_submodule"
     env.run("touch", "testfile", cwd=submodule_path)
@@ -16,8 +16,8 @@ def _create_test_package_submodule(env: PipTestEnvironment) -> Path:
     return submodule_path
 
 
-def _change_test_package_submodule(
-    env: PipTestEnvironment, submodule_path: Path
+def change_test_package_submodule(
+    env: PipTestEnvironment, submodule_path: pathlib.Path
 ) -> None:
     submodule_path.joinpath("testfile").write_text("this is a changed file")
     submodule_path.joinpath("testfile2").write_text("this is an added file")
@@ -25,8 +25,8 @@ def _change_test_package_submodule(
     _git_commit(env, submodule_path, message="submodule change")
 
 
-def _pull_in_submodule_changes_to_module(
-    env: PipTestEnvironment, module_path: Path, rel_path: str
+def pull_in_submodule_changes_to_module(
+    env: PipTestEnvironment, module_path: pathlib.Path, rel_path: str
 ) -> None:
     """
     Args:
@@ -38,9 +38,9 @@ def _pull_in_submodule_changes_to_module(
     _git_commit(env, module_path, message="submodule change", stage_modified=True)
 
 
-def _create_test_package_with_submodule(
+def create_test_package_with_submodule(
     env: PipTestEnvironment, rel_path: str
-) -> Tuple[Path, Path]:
+) -> Tuple[pathlib.Path, pathlib.Path]:
     """
     Args:
       rel_path: the location of the submodule relative to the superproject.
@@ -73,7 +73,7 @@ def _create_test_package_with_submodule(
         "git",
         "submodule",
         "add",
-        submodule_path,
+        str(submodule_path),
         rel_path,
         cwd=version_pkg_path,
     )
diff --git a/tests/lib/local_repos.py b/tests/lib/local_repos.py
index 2ead17aca0b..afcb966d832 100644
--- a/tests/lib/local_repos.py
+++ b/tests/lib/local_repos.py
@@ -1,18 +1,17 @@
 import os
+import pathlib
 import subprocess
 import urllib.request
 
 from pip._internal.utils.misc import hide_url
 from pip._internal.vcs import vcs
-from tests.lib import path_to_url
-from tests.lib.path import Path
 
 
-def _create_svn_initools_repo(initools_dir: str) -> None:
+def _create_svn_initools_repo(initools_dir: pathlib.Path) -> None:
     """
     Create the SVN INITools repo.
     """
-    directory = os.path.dirname(initools_dir)
+    directory = initools_dir.parent
     subprocess.check_call("svnadmin create INITools".split(), cwd=directory)
 
     filename, _ = urllib.request.urlretrieve(
@@ -21,7 +20,7 @@ def _create_svn_initools_repo(initools_dir: str) -> None:
     )
     with open(filename) as dump:
         subprocess.check_call(
-            ["svnadmin", "load", initools_dir],
+            ["svnadmin", "load", str(initools_dir)],
             stdin=dump,
             stdout=subprocess.DEVNULL,
         )
@@ -30,7 +29,7 @@ def _create_svn_initools_repo(initools_dir: str) -> None:
 
 def local_checkout(
     remote_repo: str,
-    temp_path: Path,
+    temp_path: pathlib.Path,
 ) -> str:
     """
     :param temp_path: the return value of the tmpdir fixture, which is a
@@ -42,23 +41,22 @@ def local_checkout(
     repository_name = os.path.basename(remote_repo)
 
     directory = temp_path.joinpath("cache")
-    repo_url_path = os.path.join(directory, repository_name)
-    assert not os.path.exists(repo_url_path)
+    repo_url_path = directory.joinpath(repository_name)
+    assert not repo_url_path.exists()
 
-    if not os.path.exists(directory):
-        os.mkdir(directory)
+    directory.mkdir(exist_ok=True)
 
     if vcs_name == "svn":
         assert repository_name == "INITools"
         _create_svn_initools_repo(repo_url_path)
-        repo_url_path = os.path.join(repo_url_path, "trunk")
+        repo_url_path = repo_url_path.joinpath("trunk")
     else:
         vcs_backend = vcs.get_backend(vcs_name)
         assert vcs_backend is not None
-        vcs_backend.obtain(repo_url_path, url=hide_url(remote_repo), verbosity=0)
+        vcs_backend.obtain(str(repo_url_path), url=hide_url(remote_repo), verbosity=0)
 
-    return "{}+{}".format(vcs_name, path_to_url(repo_url_path))
+    return "{}+{}".format(vcs_name, repo_url_path.as_uri())
 
 
-def local_repo(remote_repo: str, temp_path: Path) -> str:
+def local_repo(remote_repo: str, temp_path: pathlib.Path) -> str:
     return local_checkout(remote_repo, temp_path).split("+", 1)[1]
diff --git a/tests/lib/path.py b/tests/lib/path.py
deleted file mode 100644
index ea8c819ec74..00000000000
--- a/tests/lib/path.py
+++ /dev/null
@@ -1,190 +0,0 @@
-# Author: Aziz Köksal
-import glob
-import os
-from typing import Iterable, Iterator, Union
-
-
-class Path(str):
-    """
-    Models a path in an object oriented way.
-    """
-
-    # File system path separator: '/' or '\'.
-    sep = os.sep
-
-    # Separator in the PATH environment variable.
-    pathsep = os.pathsep
-
-    def __new__(cls, *paths: str) -> "Path":
-        if len(paths):
-            return super().__new__(cls, os.path.join(*paths))
-        return super().__new__(cls)
-
-    def __div__(self, path: str) -> "Path":
-        """
-        Joins this path with another path.
-
-        >>> path_obj / 'bc.d'
-        >>> path_obj / path_obj2
-        """
-        return Path(self, path)
-
-    __truediv__ = __div__
-
-    def __rdiv__(self, path: str) -> "Path":
-        """
-        Joins this path with another path.
-
-        >>> "/home/a" / path_obj
-        """
-        return Path(path, self)
-
-    __rtruediv__ = __rdiv__
-
-    def __idiv__(self, path: str) -> "Path":
-        """
-        Like __div__ but also assigns to the variable.
-
-        >>> path_obj /= 'bc.d'
-        """
-        return Path(self, path)
-
-    __itruediv__ = __idiv__
-
-    def __add__(self, path: str) -> "Path":
-        """
-        >>> Path('/home/a') + 'bc.d'
-        '/home/abc.d'
-        """
-        return Path(str(self) + path)
-
-    def __radd__(self, path: str) -> "Path":
-        """
-        >>> '/home/a' + Path('bc.d')
-        '/home/abc.d'
-        """
-        return Path(path + str(self))
-
-    def __repr__(self) -> str:
-        return "Path({inner})".format(inner=str.__repr__(self))
-
-    @property
-    def name(self) -> str:
-        """
-        '/home/a/bc.d' -> 'bc.d'
-        """
-        return os.path.basename(self)
-
-    @property
-    def stem(self) -> str:
-        """
-        '/home/a/bc.d' -> 'bc'
-        """
-        return Path(os.path.splitext(self)[0]).name
-
-    @property
-    def suffix(self) -> str:
-        """
-        '/home/a/bc.d' -> '.d'
-        """
-        return Path(os.path.splitext(self)[1])
-
-    def resolve(self) -> "Path":
-        """
-        Resolves symbolic links.
-        """
-        return Path(os.path.realpath(self))
-
-    @property
-    def parent(self) -> "Path":
-        """
-        Returns the parent directory of this path.
-
-        '/home/a/bc.d' -> '/home/a'
-        '/home/a/' -> '/home/a'
-        '/home/a' -> '/home'
-        """
-        return Path(os.path.dirname(self))
-
-    def exists(self) -> bool:
-        """
-        Returns True if the path exists.
-        """
-        return os.path.exists(self)
-
-    def mkdir(
-        self,
-        mode: int = 0o777,
-        exist_ok: bool = False,
-        parents: bool = False,
-    ) -> None:
-        """
-        Creates a directory, if it doesn't exist already.
-
-        :param parents: Whether to create parent directories.
-        """
-
-        maker_func = os.makedirs if parents else os.mkdir
-        try:
-            maker_func(self, mode)
-        except OSError:
-            if not exist_ok or not os.path.isdir(self):
-                raise
-
-    def unlink(self) -> None:
-        """
-        Removes a file.
-        """
-        os.remove(self)
-
-    def rmdir(self) -> None:
-        """
-        Removes a directory.
-        """
-        os.rmdir(self)
-
-    def rename(self, to: str) -> None:
-        """
-        Renames a file or directory. May throw an OSError.
-        """
-        os.rename(self, to)
-
-    def glob(self, pattern: str) -> Iterator["Path"]:
-        return (Path(i) for i in glob.iglob(self.joinpath(pattern)))
-
-    def joinpath(self, *parts: str) -> "Path":
-        return Path(self, *parts)
-
-    # TODO: Remove after removing inheritance from str.
-    def join(self, parts: Iterable[str]) -> str:
-        raise RuntimeError("Path.join is invalid, use joinpath instead.")
-
-    def read_bytes(self) -> bytes:
-        with open(self, "rb") as fp:
-            return fp.read()
-
-    def write_bytes(self, content: bytes) -> None:
-        with open(self, "wb") as f:
-            f.write(content)
-
-    def read_text(self) -> str:
-        with open(self, "r") as fp:
-            return fp.read()
-
-    def write_text(self, content: str) -> None:
-        with open(self, "w") as fp:
-            fp.write(content)
-
-    def touch(self) -> None:
-        with open(self, "a") as fp:
-            path: Union[int, str] = fp.fileno() if os.utime in os.supports_fd else self
-            os.utime(path)
-
-    def symlink_to(self, target: str) -> None:
-        os.symlink(target, self)
-
-    def stat(self) -> os.stat_result:
-        return os.stat(self)
-
-
-curdir = Path(os.path.curdir)
diff --git a/tests/lib/server.py b/tests/lib/server.py
index 95cc6a23e34..4b5add345d3 100644
--- a/tests/lib/server.py
+++ b/tests/lib/server.py
@@ -1,4 +1,4 @@
-import os
+import pathlib
 import ssl
 import threading
 from base64 import b64encode
@@ -166,46 +166,34 @@ def link(name: str, value: str) -> str:
     return text_html_response(html5_page(links))
 
 
-def file_response(path: str) -> "WSGIApplication":
+def file_response(path: pathlib.Path) -> "WSGIApplication":
     def responder(environ: "WSGIEnvironment", start_response: "StartResponse") -> Body:
-        size = os.stat(path).st_size
         start_response(
             "200 OK",
             [
                 ("Content-Type", "application/octet-stream"),
-                ("Content-Length", str(size)),
+                ("Content-Length", str(path.stat().st_size)),
             ],
         )
-
-        with open(path, "rb") as f:
-            return [f.read()]
+        return [path.read_bytes()]
 
     return responder
 
 
-def authorization_response(path: str) -> "WSGIApplication":
+def authorization_response(path: pathlib.Path) -> "WSGIApplication":
     correct_auth = "Basic " + b64encode(b"USERNAME:PASSWORD").decode("ascii")
 
     def responder(environ: "WSGIEnvironment", start_response: "StartResponse") -> Body:
-
-        if environ.get("HTTP_AUTHORIZATION") == correct_auth:
-            size = os.stat(path).st_size
-            start_response(
-                "200 OK",
-                [
-                    ("Content-Type", "application/octet-stream"),
-                    ("Content-Length", str(size)),
-                ],
-            )
-        else:
-            start_response(
-                "401 Unauthorized",
-                [
-                    ("WWW-Authenticate", "Basic"),
-                ],
-            )
-
-        with open(path, "rb") as f:
-            return [f.read()]
+        if environ.get("HTTP_AUTHORIZATION") != correct_auth:
+            start_response("401 Unauthorized", [("WWW-Authenticate", "Basic")])
+            return ()
+        start_response(
+            "200 OK",
+            [
+                ("Content-Type", "application/octet-stream"),
+                ("Content-Length", str(path.stat().st_size)),
+            ],
+        )
+        return [path.read_bytes()]
 
     return responder
diff --git a/tests/lib/test_wheel.py b/tests/lib/test_wheel.py
index 09c2ee3e610..ba8e7099290 100644
--- a/tests/lib/test_wheel.py
+++ b/tests/lib/test_wheel.py
@@ -1,12 +1,12 @@
 """Tests for wheel helper.
 """
 import csv
+import pathlib
 from email import message_from_string
 from email.message import Message
 from functools import partial
 from zipfile import ZipFile
 
-from tests.lib.path import Path
 from tests.lib.wheel import (
     File,
     _default,
@@ -145,10 +145,10 @@ def test_make_wheel_metadata_file_no_contents() -> None:
     assert f is None
 
 
-def test_make_wheel_basics(tmpdir: Path) -> None:
-    make_wheel(name="simple", version="0.1.0").save_to_dir(tmpdir)
+def test_make_wheel_basics(tmp_path: pathlib.Path) -> None:
+    make_wheel(name="simple", version="0.1.0").save_to_dir(tmp_path)
 
-    expected_wheel_path = tmpdir / "simple-0.1.0-py2.py3-none-any.whl"
+    expected_wheel_path = tmp_path / "simple-0.1.0-py2.py3-none-any.whl"
     assert expected_wheel_path.exists()
 
     with ZipFile(expected_wheel_path) as z:
diff --git a/tests/lib/venv.py b/tests/lib/venv.py
index a43aead9605..9e1c10e2b53 100644
--- a/tests/lib/venv.py
+++ b/tests/lib/venv.py
@@ -1,15 +1,14 @@
 import compileall
+import pathlib
 import shutil
 import subprocess
 import sys
 import textwrap
 import venv as _venv
-from typing import TYPE_CHECKING, Optional
+from typing import TYPE_CHECKING, Optional, Union
 
 import virtualenv as _virtualenv
 
-from .path import Path
-
 if TYPE_CHECKING:
     # Literal was introduced in Python 3.8.
     from typing import Literal
@@ -27,11 +26,11 @@ class VirtualEnvironment:
 
     def __init__(
         self,
-        location: str,
+        location: pathlib.Path,
         template: Optional["VirtualEnvironment"] = None,
         venv_type: Optional[VirtualEnvironmentType] = None,
     ):
-        self.location = Path(location)
+        self.location = location
         assert template is None or venv_type is None
         self._venv_type: VirtualEnvironmentType
         if template is not None:
@@ -48,14 +47,14 @@ def __init__(
 
     def _update_paths(self) -> None:
         home, lib, inc, bin = _virtualenv.path_locations(self.location)
-        self.bin = Path(bin)
-        self.site = Path(lib) / "site-packages"
+        self.bin = pathlib.Path(bin)
+        self.site = pathlib.Path(lib, "site-packages")
         # Workaround for https://github.com/pypa/virtualenv/issues/306
         if hasattr(sys, "pypy_version_info"):
             version_dir = str(sys.version_info.major)
-            self.lib = Path(home, "lib-python", version_dir)
+            self.lib = pathlib.Path(home, "lib-python", version_dir)
         else:
-            self.lib = Path(lib)
+            self.lib = pathlib.Path(lib)
 
     def __repr__(self) -> str:
         return f"<VirtualEnvironment {self.location}>"
@@ -171,9 +170,9 @@ def _customize_site(self) -> None:
     def clear(self) -> None:
         self._create(clear=True)
 
-    def move(self, location: str) -> None:
+    def move(self, location: Union[pathlib.Path, str]) -> None:
         shutil.move(self.location, location)
-        self.location = Path(location)
+        self.location = pathlib.Path(location)
         self._update_paths()
 
     @property
diff --git a/tests/lib/wheel.py b/tests/lib/wheel.py
index 878364cf792..c2896d7da4c 100644
--- a/tests/lib/wheel.py
+++ b/tests/lib/wheel.py
@@ -2,6 +2,7 @@
 """
 import csv
 import itertools
+import pathlib
 from base64 import urlsafe_b64encode
 from collections import namedtuple
 from copy import deepcopy
@@ -26,7 +27,6 @@
 from pip._vendor.requests.structures import CaseInsensitiveDict
 
 from pip._internal.metadata import BaseDistribution, MemoryWheel, get_wheel_distribution
-from tests.lib.path import Path
 
 # As would be used in metadata
 HeaderValue = Union[str, List[str]]
@@ -252,23 +252,23 @@ def __init__(self, name: str, files: Iterable[File]) -> None:
         self._name = name
         self._files = files
 
-    def save_to_dir(self, path: Union[Path, str]) -> str:
+    def save_to_dir(self, path: Union[pathlib.Path, str]) -> str:
         """Generate wheel file with correct name and save into the provided
         directory.
 
         :returns the wheel file path
         """
-        p = Path(path) / self._name
+        p = pathlib.Path(path, self._name)
         p.write_bytes(self.as_bytes())
         return str(p)
 
-    def save_to(self, path: Union[Path, str]) -> str:
+    def save_to(self, path: Union[pathlib.Path, str]) -> str:
         """Generate wheel file, saving to the provided path. Any parent
         directories must already exist.
 
         :returns the wheel file path
         """
-        path = Path(path)
+        path = pathlib.Path(path)
         path.write_bytes(self.as_bytes())
         return str(path)
 
diff --git a/tests/unit/resolution_resolvelib/test_requirement.py b/tests/unit/resolution_resolvelib/test_requirement.py
index 387afbc2304..a3656d4d6bb 100644
--- a/tests/unit/resolution_resolvelib/test_requirement.py
+++ b/tests/unit/resolution_resolvelib/test_requirement.py
@@ -1,3 +1,4 @@
+import pathlib
 from typing import Iterator, List, Tuple
 
 import pytest
@@ -6,9 +7,7 @@
 from pip._internal.resolution.resolvelib.base import Candidate, Constraint, Requirement
 from pip._internal.resolution.resolvelib.factory import Factory
 from pip._internal.resolution.resolvelib.provider import PipProvider
-from pip._internal.utils.urls import path_to_url
 from tests.lib import TestData
-from tests.lib.path import Path
 
 # NOTE: All tests are prefixed `test_rlr` (for "test resolvelib resolver").
 #       This helps select just these tests using pytest's `-k` option, and
@@ -25,11 +24,11 @@
 
 @pytest.fixture
 def test_cases(data: TestData) -> Iterator[List[Tuple[str, str, int]]]:
-    def data_file(name: str) -> Path:
+    def data_file(name: str) -> pathlib.Path:
         return data.packages.joinpath(name)
 
     def data_url(name: str) -> str:
-        return path_to_url(data_file(name))
+        return data_file(name).as_uri()
 
     test_cases = [
         # requirement, name, matches
@@ -38,14 +37,14 @@ def data_url(name: str) -> str:
         ("simple>1.0", "simple", 2),
         # ("simple[extra]==1.0", "simple[extra]", 1),
         # Wheels
-        (data_file("simplewheel-1.0-py2.py3-none-any.whl"), "simplewheel", 1),
+        (str(data_file("simplewheel-1.0-py2.py3-none-any.whl")), "simplewheel", 1),
         (data_url("simplewheel-1.0-py2.py3-none-any.whl"), "simplewheel", 1),
         # Direct URLs
         # TODO: The following test fails
         # ("foo @ " + data_url("simple-1.0.tar.gz"), "foo", 1),
         # SDists
         # TODO: sdists should have a name
-        (data_file("simple-1.0.tar.gz"), "simple", 1),
+        (str(data_file("simple-1.0.tar.gz")), "simple", 1),
         (data_url("simple-1.0.tar.gz"), "simple", 1),
         # TODO: directory, editables
     ]
diff --git a/tests/unit/test_base_command.py b/tests/unit/test_base_command.py
index 9a61ccc77b4..907e0e8391b 100644
--- a/tests/unit/test_base_command.py
+++ b/tests/unit/test_base_command.py
@@ -1,5 +1,6 @@
 import logging
 import os
+import pathlib
 from optparse import Values
 from typing import Callable, Iterator, List, NoReturn, Optional
 from unittest.mock import Mock, patch
@@ -11,7 +12,6 @@
 from pip._internal.utils import temp_dir
 from pip._internal.utils.logging import BrokenStdoutLoggingError
 from pip._internal.utils.temp_dir import TempDirectory
-from tests.lib.path import Path
 
 
 @pytest.fixture
@@ -103,40 +103,44 @@ def test_handle_pip_version_check_called(mock_handle_version_check: Mock) -> Non
     mock_handle_version_check.assert_called_once()
 
 
-def test_log_command_success(fixed_time: None, tmpdir: Path) -> None:
+@pytest.mark.usefixtures("fixed_time")
+def test_log_command_success(tmp_path: pathlib.Path) -> None:
     """Test the --log option logs when command succeeds."""
     cmd = FakeCommand()
-    log_path = tmpdir.joinpath("log")
-    cmd.main(["fake", "--log", log_path])
+    log_path = tmp_path.joinpath("log")
+    cmd.main(["fake", "--log", str(log_path)])
     with open(log_path) as f:
         assert f.read().rstrip() == "2019-01-17T06:00:37,040 fake"
 
 
-def test_log_command_error(fixed_time: None, tmpdir: Path) -> None:
+@pytest.mark.usefixtures("fixed_time")
+def test_log_command_error(tmp_path: pathlib.Path) -> None:
     """Test the --log option logs when command fails."""
     cmd = FakeCommand(error=True)
-    log_path = tmpdir.joinpath("log")
-    cmd.main(["fake", "--log", log_path])
+    log_path = tmp_path.joinpath("log")
+    cmd.main(["fake", "--log", str(log_path)])
     with open(log_path) as f:
         assert f.read().startswith("2019-01-17T06:00:37,040 fake")
 
 
-def test_log_file_command_error(fixed_time: None, tmpdir: Path) -> None:
+@pytest.mark.usefixtures("fixed_time")
+def test_log_file_command_error(tmp_path: pathlib.Path) -> None:
     """Test the --log-file option logs (when there's an error)."""
     cmd = FakeCommand(error=True)
-    log_file_path = tmpdir.joinpath("log_file")
-    cmd.main(["fake", "--log-file", log_file_path])
+    log_file_path = tmp_path.joinpath("log_file")
+    cmd.main(["fake", "--log-file", str(log_file_path)])
     with open(log_file_path) as f:
         assert f.read().startswith("2019-01-17T06:00:37,040 fake")
 
 
-def test_log_unicode_messages(fixed_time: None, tmpdir: Path) -> None:
+@pytest.mark.usefixtures("fixed_time")
+def test_log_unicode_messages(tmp_path: pathlib.Path) -> None:
     """Tests that logging bytestrings and unicode objects
     don't break logging.
     """
     cmd = FakeCommandWithUnicode()
-    log_path = tmpdir.joinpath("log")
-    cmd.main(["fake_unicode", "--log", log_path])
+    log_path = tmp_path.joinpath("log")
+    cmd.main(["fake_unicode", "--log", str(log_path)])
 
 
 @pytest.mark.no_auto_tempdir_manager
diff --git a/tests/unit/test_cache.py b/tests/unit/test_cache.py
index acb16034186..5eda328979f 100644
--- a/tests/unit/test_cache.py
+++ b/tests/unit/test_cache.py
@@ -1,4 +1,5 @@
 import os
+import pathlib
 
 from pip._vendor.packaging.tags import Tag
 
@@ -6,7 +7,6 @@
 from pip._internal.models.format_control import FormatControl
 from pip._internal.models.link import Link
 from pip._internal.utils.misc import ensure_dir
-from tests.lib.path import Path
 
 
 def test_falsey_path_none() -> None:
@@ -24,12 +24,12 @@ def test_subdirectory_fragment() -> None:
     assert wc.get_path_for_link(link1) != wc.get_path_for_link(link2)
 
 
-def test_wheel_name_filter(tmpdir: Path) -> None:
+def test_wheel_name_filter(tmp_path: pathlib.Path) -> None:
     """
     Test the wheel cache filters on wheel name when several wheels
     for different package are stored under the same cache directory.
     """
-    wc = WheelCache(tmpdir, FormatControl())
+    wc = WheelCache(str(tmp_path), FormatControl())
     link = Link("https://g.c/package.tar.gz")
     cache_path = wc.get_path_for_link(link)
     ensure_dir(cache_path)
@@ -52,8 +52,8 @@ def test_cache_hash() -> None:
     assert h == "f83b32dfa27a426dec08c21bf006065dd003d0aac78e7fc493d9014d"
 
 
-def test_get_cache_entry(tmpdir: Path) -> None:
-    wc = WheelCache(tmpdir, FormatControl())
+def test_get_cache_entry(tmp_path: pathlib.Path) -> None:
+    wc = WheelCache(str(tmp_path), FormatControl())
     persi_link = Link("https://g.c/o/r/persi")
     persi_path = wc.get_path_for_link(persi_link)
     ensure_dir(persi_path)
diff --git a/tests/unit/test_collector.py b/tests/unit/test_collector.py
index f77794b55b9..8194689e0a5 100644
--- a/tests/unit/test_collector.py
+++ b/tests/unit/test_collector.py
@@ -1,8 +1,8 @@
 import itertools
 import logging
-import os.path
+import os
+import pathlib
 import re
-import urllib.request
 import uuid
 from textwrap import dedent
 from typing import List, Optional, Tuple
@@ -31,7 +31,6 @@
 from pip._internal.models.link import Link
 from pip._internal.network.session import PipSession
 from tests.lib import TestData, make_test_link_collector
-from tests.lib.path import Path
 
 
 @pytest.mark.parametrize(
@@ -668,13 +667,11 @@ def make_fake_html_response(url: str) -> mock.Mock:
     return mock.Mock(content=content, url=url, headers={})
 
 
-def test_get_html_page_directory_append_index(tmpdir: Path) -> None:
+def test_get_html_page_directory_append_index(tmp_path: pathlib.Path) -> None:
     """`_get_html_page()` should append "index.html" to a directory URL."""
-    dirpath = tmpdir / "something"
+    dirpath = tmp_path / "something"
     dirpath.mkdir()
-    dir_url = "file:///{}".format(
-        urllib.request.pathname2url(dirpath).lstrip("/"),
-    )
+    dir_url = dirpath.as_uri()
     expected_url = "{}/index.html".format(dir_url.rstrip("/"))
 
     session = mock.Mock(PipSession)
@@ -757,7 +754,7 @@ def test_collect_sources__non_existing_path() -> None:
             index_url="ignored-by-no-index",
             extra_index_urls=[],
             no_index=True,
-            find_links=[os.path.join("this", "doesnt", "exist")],
+            find_links=["this/doesnt/exist"],
         ),
     )
     sources = collector.collect_sources(
@@ -901,7 +898,7 @@ def test_link_collector_create(
 
 @mock.patch("os.path.expanduser")
 def test_link_collector_create_find_links_expansion(
-    mock_expanduser: mock.Mock, tmpdir: Path
+    mock_expanduser: mock.Mock, tmp_path: pathlib.Path
 ) -> None:
     """
     Test "~" expansion in --find-links paths.
@@ -909,7 +906,7 @@ def test_link_collector_create_find_links_expansion(
     # This is a mock version of expanduser() that expands "~" to the tmpdir.
     def expand_path(path: str) -> str:
         if path.startswith("~/"):
-            path = os.path.join(tmpdir, path[2:])
+            path = os.path.join(tmp_path, path[2:])
         return path
 
     mock_expanduser.side_effect = expand_path
@@ -923,8 +920,8 @@ def expand_path(path: str) -> str:
     )
     # Only create temp2 and not temp1 to test that "~" expansion only occurs
     # when the directory exists.
-    temp2_dir = os.path.join(tmpdir, "temp2")
-    os.mkdir(temp2_dir)
+    temp2_dir = tmp_path.joinpath("temp2")
+    temp2_dir.mkdir()
 
     link_collector = LinkCollector.create(session, options=options)
 
diff --git a/tests/unit/test_compat.py b/tests/unit/test_compat.py
index da58cc8d3b3..b984b8c93f5 100644
--- a/tests/unit/test_compat.py
+++ b/tests/unit/test_compat.py
@@ -1,9 +1,9 @@
 import os
+import pathlib
 
 import pytest
 
 from pip._internal.utils.compat import get_path_uid
-from tests.lib.path import Path
 
 
 def test_get_path_uid() -> None:
@@ -21,11 +21,11 @@ def test_get_path_uid_without_NOFOLLOW(monkeypatch: pytest.MonkeyPatch) -> None:
 # Skip unconditionally on Windows, as symlinks need admin privs there
 @pytest.mark.skipif("sys.platform == 'win32'")
 @pytest.mark.skipif("not hasattr(os, 'symlink')")
-def test_get_path_uid_symlink(tmpdir: Path) -> None:
-    f = tmpdir / "symlink" / "somefile"
+def test_get_path_uid_symlink(tmp_path: pathlib.Path) -> None:
+    f = tmp_path / "symlink" / "somefile"
     f.parent.mkdir()
     f.write_text("content")
-    fs = f + "_link"
+    fs = f"{f}_link"
     os.symlink(f, fs)
     with pytest.raises(OSError):
         get_path_uid(fs)
@@ -34,13 +34,13 @@ def test_get_path_uid_symlink(tmpdir: Path) -> None:
 @pytest.mark.skipif("not hasattr(os, 'O_NOFOLLOW')")
 @pytest.mark.skipif("not hasattr(os, 'symlink')")
 def test_get_path_uid_symlink_without_NOFOLLOW(
-    tmpdir: Path, monkeypatch: pytest.MonkeyPatch
+    tmp_path: pathlib.Path, monkeypatch: pytest.MonkeyPatch
 ) -> None:
     monkeypatch.delattr("os.O_NOFOLLOW")
-    f = tmpdir / "symlink" / "somefile"
+    f = tmp_path / "symlink" / "somefile"
     f.parent.mkdir()
     f.write_text("content")
-    fs = f + "_link"
+    fs = f"{f}_link"
     os.symlink(f, fs)
     with pytest.raises(OSError):
         get_path_uid(fs)
diff --git a/tests/unit/test_direct_url_helpers.py b/tests/unit/test_direct_url_helpers.py
index 8d94aeb50b6..11714504aa9 100644
--- a/tests/unit/test_direct_url_helpers.py
+++ b/tests/unit/test_direct_url_helpers.py
@@ -1,3 +1,4 @@
+import pathlib
 from functools import partial
 from unittest import mock
 
@@ -7,9 +8,7 @@
     direct_url_as_pep440_direct_reference,
     direct_url_from_link,
 )
-from pip._internal.utils.urls import path_to_url
 from tests.lib import PipTestEnvironment
-from tests.lib.path import Path
 
 
 def test_as_pep440_requirement_archive() -> None:
@@ -112,9 +111,9 @@ def test_from_link_vcs(mock_get_backend_for_scheme: mock.Mock) -> None:
 
 
 def test_from_link_vcs_with_source_dir_obtains_commit_id(
-    script: PipTestEnvironment, tmpdir: Path
+    script: PipTestEnvironment, tmp_path: pathlib.Path
 ) -> None:
-    repo_path = tmpdir / "test-repo"
+    repo_path = tmp_path / "test-repo"
     repo_path.mkdir()
     repo_dir = str(repo_path)
     script.run("git", "init", cwd=repo_dir)
@@ -150,8 +149,8 @@ def test_from_link_archive() -> None:
     assert direct_url.info.hash == "sha1=1b8c5bc61a86f377fea47b4276c8c8a5842d2220"
 
 
-def test_from_link_dir(tmpdir: Path) -> None:
-    dir_url = path_to_url(tmpdir)
+def test_from_link_dir(tmp_path: pathlib.Path) -> None:
+    dir_url = tmp_path.as_uri()
     direct_url = direct_url_from_link(Link(dir_url))
     assert direct_url.url == dir_url
     assert isinstance(direct_url.info, DirInfo)
diff --git a/tests/unit/test_locations.py b/tests/unit/test_locations.py
index 023b6687d41..6b6b71cb800 100644
--- a/tests/unit/test_locations.py
+++ b/tests/unit/test_locations.py
@@ -4,6 +4,7 @@
 """
 import getpass
 import os
+import pathlib
 import shutil
 import sys
 import sysconfig
@@ -14,7 +15,6 @@
 import pytest
 
 from pip._internal.locations import SCHEME_KEYS, _should_use_sysconfig, get_scheme
-from tests.lib.path import Path
 
 if sys.platform == "win32":
     pwd = Mock()
@@ -119,13 +119,13 @@ def test_root_modifies_appropriately(self) -> None:
     @pytest.mark.incompatible_with_sysconfig
     @pytest.mark.incompatible_with_venv
     def test_distutils_config_file_read(
-        self, tmpdir: Path, monkeypatch: pytest.MonkeyPatch
+        self, tmp_path: pathlib.Path, monkeypatch: pytest.MonkeyPatch
     ) -> None:
         # This deals with nt/posix path differences
         install_scripts = os.path.normcase(
             os.path.abspath(os.path.join(os.path.sep, "somewhere", "else"))
         )
-        f = tmpdir / "config" / "setup.cfg"
+        f = tmp_path / "config" / "setup.cfg"
         f.parent.mkdir()
         f.write_text("[install]\ninstall-scripts=" + install_scripts)
         from distutils.dist import Distribution
@@ -145,13 +145,13 @@ def test_distutils_config_file_read(
     # .so) into that path; i.e. ensure platlib & purelib are set to
     # this path. sysconfig does not support this.
     def test_install_lib_takes_precedence(
-        self, tmpdir: Path, monkeypatch: pytest.MonkeyPatch
+        self, tmp_path: pathlib.Path, monkeypatch: pytest.MonkeyPatch
     ) -> None:
         # This deals with nt/posix path differences
         install_lib = os.path.normcase(
             os.path.abspath(os.path.join(os.path.sep, "somewhere", "else"))
         )
-        f = tmpdir / "config" / "setup.cfg"
+        f = tmp_path / "config" / "setup.cfg"
         f.parent.mkdir()
         f.write_text("[install]\ninstall-lib=" + install_lib)
         from distutils.dist import Distribution
diff --git a/tests/unit/test_network_cache.py b/tests/unit/test_network_cache.py
index c7e0e382b17..28a1b7938cf 100644
--- a/tests/unit/test_network_cache.py
+++ b/tests/unit/test_network_cache.py
@@ -1,4 +1,5 @@
 import os
+import pathlib
 from typing import Iterator
 from unittest.mock import Mock
 
@@ -6,12 +7,11 @@
 from pip._vendor.cachecontrol.caches import FileCache
 
 from pip._internal.network.cache import SafeFileCache
-from tests.lib.path import Path
 
 
 @pytest.fixture(scope="function")
-def cache_tmpdir(tmpdir: Path) -> Iterator[Path]:
-    cache_dir = tmpdir.joinpath("cache")
+def cache_tmp_path(tmp_path: pathlib.Path) -> Iterator[pathlib.Path]:
+    cache_dir = tmp_path.joinpath("cache")
     cache_dir.mkdir(parents=True)
     yield cache_dir
 
@@ -23,9 +23,9 @@ class TestSafeFileCache:
     os.geteuid which is absent on Windows.
     """
 
-    def test_cache_roundtrip(self, cache_tmpdir: Path) -> None:
+    def test_cache_roundtrip(self, cache_tmp_path: pathlib.Path) -> None:
 
-        cache = SafeFileCache(cache_tmpdir)
+        cache = SafeFileCache(str(cache_tmp_path))
         assert cache.get("test key") is None
         cache.set("test key", b"a test string")
         assert cache.get("test key") == b"a test string"
@@ -34,31 +34,31 @@ def test_cache_roundtrip(self, cache_tmpdir: Path) -> None:
 
     @pytest.mark.skipif("sys.platform == 'win32'")
     def test_safe_get_no_perms(
-        self, cache_tmpdir: Path, monkeypatch: pytest.MonkeyPatch
+        self, cache_tmp_path: pathlib.Path, monkeypatch: pytest.MonkeyPatch
     ) -> None:
-        os.chmod(cache_tmpdir, 000)
+        os.chmod(cache_tmp_path, 000)
 
         monkeypatch.setattr(os.path, "exists", lambda x: True)
 
-        cache = SafeFileCache(cache_tmpdir)
+        cache = SafeFileCache(str(cache_tmp_path))
         cache.get("foo")
 
     @pytest.mark.skipif("sys.platform == 'win32'")
-    def test_safe_set_no_perms(self, cache_tmpdir: Path) -> None:
-        os.chmod(cache_tmpdir, 000)
+    def test_safe_set_no_perms(self, cache_tmp_path: pathlib.Path) -> None:
+        os.chmod(cache_tmp_path, 000)
 
-        cache = SafeFileCache(cache_tmpdir)
+        cache = SafeFileCache(str(cache_tmp_path))
         cache.set("foo", b"bar")
 
     @pytest.mark.skipif("sys.platform == 'win32'")
-    def test_safe_delete_no_perms(self, cache_tmpdir: Path) -> None:
-        os.chmod(cache_tmpdir, 000)
+    def test_safe_delete_no_perms(self, cache_tmp_path: pathlib.Path) -> None:
+        os.chmod(cache_tmp_path, 000)
 
-        cache = SafeFileCache(cache_tmpdir)
+        cache = SafeFileCache(str(cache_tmp_path))
         cache.delete("foo")
 
-    def test_cache_hashes_are_same(self, cache_tmpdir: Path) -> None:
-        cache = SafeFileCache(cache_tmpdir)
+    def test_cache_hashes_are_same(self, cache_tmp_path: pathlib.Path) -> None:
+        cache = SafeFileCache(str(cache_tmp_path))
         key = "test key"
         fake_cache = Mock(FileCache, directory=cache.directory, encode=FileCache.encode)
         assert cache._get_cache_path(key) == FileCache._fn(fake_cache, key)
diff --git a/tests/unit/test_network_session.py b/tests/unit/test_network_session.py
index 18eb9539f7f..a529cc5e3f4 100644
--- a/tests/unit/test_network_session.py
+++ b/tests/unit/test_network_session.py
@@ -1,4 +1,5 @@
 import logging
+import pathlib
 from typing import Any, List, Optional
 from urllib.parse import urlparse
 from urllib.request import getproxies
@@ -9,7 +10,6 @@
 from pip import __version__
 from pip._internal.models.link import Link
 from pip._internal.network.session import CI_ENVIRONMENT_VARIABLES, PipSession
-from tests.lib.path import Path
 
 
 def get_user_agent() -> str:
@@ -67,22 +67,18 @@ def test_cache_defaults_off(self) -> None:
         assert not hasattr(session.adapters["http://"], "cache")
         assert not hasattr(session.adapters["https://"], "cache")
 
-    def test_cache_is_enabled(self, tmpdir: Path) -> None:
-        cache_directory = tmpdir.joinpath("test-cache")
-        session = PipSession(cache=cache_directory)
-
-        assert hasattr(session.adapters["https://"], "cache")
-
-        assert session.adapters["https://"].cache.directory == cache_directory
-
-    def test_http_cache_is_not_enabled(self, tmpdir: Path) -> None:
-        session = PipSession(cache=tmpdir.joinpath("test-cache"))
+    def test_cache_is_enabled(self, tmp_path: pathlib.Path) -> None:
+        cache_directory = tmp_path.joinpath("test-cache")
+        session = PipSession(cache=str(cache_directory))
+        assert session.adapters["https://"].cache.directory == str(cache_directory)
 
+    def test_http_cache_is_not_enabled(self, tmp_path: pathlib.Path) -> None:
+        session = PipSession(cache=str(tmp_path.joinpath("test-cache")))
         assert not hasattr(session.adapters["http://"], "cache")
 
-    def test_trusted_hosts_adapter(self, tmpdir: Path) -> None:
+    def test_trusted_hosts_adapter(self, tmp_path: pathlib.Path) -> None:
         session = PipSession(
-            cache=tmpdir.joinpath("test-cache"),
+            cache=str(tmp_path.joinpath("test-cache")),
             trusted_hosts=["example.com"],
         )
 
diff --git a/tests/unit/test_operations_prepare.py b/tests/unit/test_operations_prepare.py
index 8838fa9ce0e..30263fb8c3e 100644
--- a/tests/unit/test_operations_prepare.py
+++ b/tests/unit/test_operations_prepare.py
@@ -1,4 +1,5 @@
 import os
+import pathlib
 import shutil
 from shutil import rmtree
 from tempfile import mkdtemp
@@ -13,9 +14,7 @@
 from pip._internal.network.session import PipSession
 from pip._internal.operations.prepare import unpack_url
 from pip._internal.utils.hashes import Hashes
-from pip._internal.utils.urls import path_to_url
 from tests.lib import TestData
-from tests.lib.path import Path
 from tests.lib.requests_mocks import MockResponse
 
 
@@ -34,7 +33,7 @@ def _fake_session_get(*args: Any, **kwargs: Any) -> Dict[str, str]:
     session.get = _fake_session_get
     download = Downloader(session, progress_bar="on")
 
-    uri = path_to_url(data.packages.joinpath("simple-1.0.tar.gz"))
+    uri = data.packages.joinpath("simple-1.0.tar.gz").as_uri()
     link = Link(uri)
     temp_dir = mkdtemp()
     try:
@@ -58,7 +57,7 @@ def _fake_session_get(*args: Any, **kwargs: Any) -> Dict[str, str]:
 
 @patch("pip._internal.network.download.raise_for_status")
 def test_download_http_url__no_directory_traversal(
-    mock_raise_for_status: Mock, tmpdir: Path
+    mock_raise_for_status: Mock, tmp_path: pathlib.Path
 ) -> None:
     """
     Test that directory traversal doesn't happen on download when the
@@ -80,18 +79,22 @@ def test_download_http_url__no_directory_traversal(
     session.get.return_value = resp
     download = Downloader(session, progress_bar="on")
 
-    download_dir = tmpdir.joinpath("download")
-    os.mkdir(download_dir)
-    file_path, content_type = download(link, download_dir)
+    download_dir = tmp_path.joinpath("download")
+    download_dir.mkdir()
+
+    download(link, str(download_dir))
+
     # The file should be downloaded to download_dir.
-    actual = os.listdir(download_dir)
-    assert actual == ["out_dir_file"]
+    assert os.listdir(download_dir) == ["out_dir_file"]
     mock_raise_for_status.assert_called_once_with(resp)
 
 
 @pytest.fixture
-def clean_project(tmpdir_factory: pytest.TempdirFactory, data: TestData) -> Path:
-    tmpdir = Path(str(tmpdir_factory.mktemp("clean_project")))
+def clean_project(
+    tmp_path_factory: pytest.TempPathFactory,
+    data: TestData,
+) -> pathlib.Path:
+    tmpdir = pathlib.Path(str(tmp_path_factory.mktemp("clean_project")))
     new_project_dir = tmpdir.joinpath("FSPkg")
     path = data.packages.joinpath("FSPkg")
     shutil.copytree(path, new_project_dir)
@@ -99,36 +102,40 @@ def clean_project(tmpdir_factory: pytest.TempdirFactory, data: TestData) -> Path
 
 
 class Test_unpack_url:
-    def prep(self, tmpdir: Path, data: TestData) -> None:
-        self.build_dir = tmpdir.joinpath("build")
-        self.download_dir = tmpdir.joinpath("download")
-        os.mkdir(self.build_dir)
-        os.mkdir(self.download_dir)
+    def prep(self, tmp_path: pathlib.Path, data: TestData) -> None:
+        self.build_dir = tmp_path.joinpath("build")
+        self.download_dir = tmp_path.joinpath("download")
+        self.build_dir.mkdir()
+        self.download_dir.mkdir()
         self.dist_file = "simple-1.0.tar.gz"
         self.dist_file2 = "simple-2.0.tar.gz"
         self.dist_path = data.packages.joinpath(self.dist_file)
         self.dist_path2 = data.packages.joinpath(self.dist_file2)
-        self.dist_url = Link(path_to_url(self.dist_path))
-        self.dist_url2 = Link(path_to_url(self.dist_path2))
+        self.dist_url = Link(self.dist_path.as_uri())
+        self.dist_url2 = Link(self.dist_path2.as_uri())
         self.no_download = Mock(side_effect=AssertionError)
 
-    def test_unpack_url_no_download(self, tmpdir: Path, data: TestData) -> None:
-        self.prep(tmpdir, data)
-        unpack_url(self.dist_url, self.build_dir, self.no_download, verbosity=0)
-        assert os.path.isdir(os.path.join(self.build_dir, "simple"))
-        assert not os.path.isfile(os.path.join(self.download_dir, self.dist_file))
-
-    def test_unpack_url_bad_hash(self, tmpdir: Path, data: TestData) -> None:
+    def test_unpack_url_no_download(
+        self,
+        tmp_path: pathlib.Path,
+        data: TestData,
+    ) -> None:
+        self.prep(tmp_path, data)
+        unpack_url(self.dist_url, str(self.build_dir), self.no_download, verbosity=0)
+        assert self.build_dir.joinpath("simple").is_dir()
+        assert not self.download_dir.joinpath(self.dist_file).exists()
+
+    def test_unpack_url_bad_hash(self, tmp_path: pathlib.Path, data: TestData) -> None:
         """
         Test when the file url hash fragment is wrong
         """
-        self.prep(tmpdir, data)
+        self.prep(tmp_path, data)
         url = f"{self.dist_url.url}#md5=bogus"
         dist_url = Link(url)
         with pytest.raises(HashMismatch):
             unpack_url(
                 dist_url,
-                self.build_dir,
+                str(self.build_dir),
                 download=self.no_download,
                 hashes=Hashes({"md5": ["bogus"]}),
                 verbosity=0,
diff --git a/tests/unit/test_options.py b/tests/unit/test_options.py
index ddcc8532cfd..ada5e1c3076 100644
--- a/tests/unit/test_options.py
+++ b/tests/unit/test_options.py
@@ -12,7 +12,6 @@
 from pip._internal.commands.configuration import ConfigurationCommand
 from pip._internal.exceptions import PipError
 from tests.lib.options_helpers import AddFakeCommandMixin
-from tests.lib.path import Path
 
 
 @contextmanager
@@ -33,7 +32,7 @@ def assert_option_error(
     assert expected in stderr
 
 
-def assert_is_default_cache_dir(value: Path) -> None:
+def assert_is_default_cache_dir(value: str) -> None:
     # This path looks different on different platforms, but the path always
     # has the substring "pip".
     assert "pip" in value
diff --git a/tests/unit/test_pep517.py b/tests/unit/test_pep517.py
index 9305cf2a19b..e048b6aae75 100644
--- a/tests/unit/test_pep517.py
+++ b/tests/unit/test_pep517.py
@@ -1,3 +1,4 @@
+import pathlib
 from textwrap import dedent
 
 import pytest
@@ -5,7 +6,6 @@
 from pip._internal.exceptions import InstallationError, InvalidPyProjectBuildRequires
 from pip._internal.req import InstallRequirement
 from tests.lib import TestData
-from tests.lib.path import Path
 
 
 @pytest.mark.parametrize(
@@ -22,7 +22,7 @@ def test_use_pep517(shared_data: TestData, source: str, expected: bool) -> None:
     """
     src = shared_data.src.joinpath(source)
     req = InstallRequirement(None, None)
-    req.source_dir = src  # make req believe it has been unpacked
+    req.source_dir = str(src)  # make req believe it has been unpacked
     req.load_pyproject_toml()
     assert req.use_pep517 is expected
 
@@ -33,7 +33,7 @@ def test_use_pep517_rejects_setup_cfg_only(shared_data: TestData) -> None:
     """
     src = shared_data.src.joinpath("pep517_setup_cfg_only")
     req = InstallRequirement(None, None)
-    req.source_dir = src  # make req believe it has been unpacked
+    req.source_dir = str(src)  # make req believe it has been unpacked
     with pytest.raises(InstallationError) as e:
         req.load_pyproject_toml()
     err_msg = e.value.args[0]
@@ -56,7 +56,7 @@ def test_disabling_pep517_invalid(shared_data: TestData, source: str, msg: str)
     """
     src = shared_data.src.joinpath(source)
     req = InstallRequirement(None, None)
-    req.source_dir = src  # make req believe it has been unpacked
+    req.source_dir = str(src)  # make req believe it has been unpacked
 
     # Simulate --no-use-pep517
     req.use_pep517 = False
@@ -72,8 +72,8 @@ def test_disabling_pep517_invalid(shared_data: TestData, source: str, msg: str)
 @pytest.mark.parametrize(
     ("spec",), [("./foo",), ("git+https://example.com/pkg@dev#egg=myproj",)]
 )
-def test_pep517_parsing_checks_requirements(tmpdir: Path, spec: str) -> None:
-    tmpdir.joinpath("pyproject.toml").write_text(
+def test_pep517_parsing_checks_requirements(tmp_path: pathlib.Path, spec: str) -> None:
+    tmp_path.joinpath("pyproject.toml").write_text(
         dedent(
             f"""
             [build-system]
@@ -83,7 +83,7 @@ def test_pep517_parsing_checks_requirements(tmpdir: Path, spec: str) -> None:
         )
     )
     req = InstallRequirement(None, None)
-    req.source_dir = tmpdir  # make req believe it has been unpacked
+    req.source_dir = str(tmp_path)  # make req believe it has been unpacked
 
     with pytest.raises(InvalidPyProjectBuildRequires) as e:
         req.load_pyproject_toml()
diff --git a/tests/unit/test_req.py b/tests/unit/test_req.py
index 18932bb344d..2719329ce2e 100644
--- a/tests/unit/test_req.py
+++ b/tests/unit/test_req.py
@@ -1,6 +1,7 @@
 import contextlib
 import email.message
 import os
+import pathlib
 import shutil
 import sys
 import tempfile
@@ -45,9 +46,7 @@
     handle_requirement_line,
 )
 from pip._internal.resolution.legacy.resolver import Resolver
-from pip._internal.utils.urls import path_to_url
 from tests.lib import TestData, make_test_finder, requirements_file, wheel
-from tests.lib.path import Path
 
 
 def get_processed_req_from_line(
@@ -150,7 +149,9 @@ def test_environment_marker_extras(self, data: TestData) -> None:
         non-wheel installs.
         """
         reqset = RequirementSet()
-        req = install_req_from_editable(data.packages.joinpath("LocalEnvironMarker"))
+        req = install_req_from_editable(
+            str(data.packages.joinpath("LocalEnvironMarker")),
+        )
         req.user_supplied = True
         reqset.add_unnamed_requirement(req)
         finder = make_test_finder(find_links=[data.find_links])
@@ -182,7 +183,7 @@ def test_missing_hash_with_require_hashes(self, data: TestData) -> None:
                 resolver.resolve(reqset.all_requirements, True)
 
     def test_missing_hash_with_require_hashes_in_reqs_file(
-        self, data: TestData, tmpdir: Path
+        self, data: TestData, tmp_path: pathlib.Path
     ) -> None:
         """--require-hashes in a requirements file should make its way to the
         RequirementSet.
@@ -190,8 +191,8 @@ def test_missing_hash_with_require_hashes_in_reqs_file(
         finder = make_test_finder(find_links=[data.find_links])
         session = finder._link_collector.session
         command = cast(InstallCommand, create_command("install"))
-        with requirements_file("--require-hashes", tmpdir) as reqs_file:
-            options, args = command.parse_args(["-r", reqs_file])
+        with requirements_file("--require-hashes", tmp_path) as reqs_file:
+            options, args = command.parse_args(["-r", str(reqs_file)])
             command.get_requirements(args, options, finder, session)
         assert options.require_hashes
 
@@ -275,7 +276,7 @@ def test_unpinned_hash_checking(self, data: TestData) -> None:
 
     def test_hash_mismatch(self, data: TestData) -> None:
         """A hash mismatch should raise an error."""
-        file_url = path_to_url((data.packages / "simple-1.0.tar.gz").resolve())
+        file_url = data.packages.joinpath("simple-1.0.tar.gz").resolve().as_uri()
         reqset = RequirementSet()
         reqset.add_unnamed_requirement(
             get_processed_req_from_line(
@@ -397,14 +398,14 @@ def test_download_info_web_archive(self) -> None:
             )
 
     def test_download_info_archive_legacy_cache(
-        self, tmp_path: Path, shared_data: TestData
+        self, tmp_path: pathlib.Path, shared_data: TestData
     ) -> None:
         """Test download_info hash is not set for an archive with legacy cache entry."""
-        url = path_to_url(shared_data.packages / "simple-1.0.tar.gz")
+        url = shared_data.packages.joinpath("simple-1.0.tar.gz").as_uri()
         finder = make_test_finder()
         wheel_cache = WheelCache(str(tmp_path / "cache"), FormatControl())
         cache_entry_dir = wheel_cache.get_path_for_link(Link(url))
-        Path(cache_entry_dir).mkdir(parents=True)
+        pathlib.Path(cache_entry_dir).mkdir(parents=True)
         wheel.make_wheel(name="simple", version="1.0").save_to_dir(cache_entry_dir)
         with self._basic_resolver(finder, wheel_cache=wheel_cache) as resolver:
             ireq = get_processed_req_from_line(f"simple @ {url}")
@@ -418,17 +419,17 @@ def test_download_info_archive_legacy_cache(
             assert not req.download_info.info.hash
 
     def test_download_info_archive_cache_with_origin(
-        self, tmp_path: Path, shared_data: TestData
+        self, tmp_path: pathlib.Path, shared_data: TestData
     ) -> None:
         """Test download_info hash is set for a web archive with cache entry
         that has origin.json."""
-        url = path_to_url(shared_data.packages / "simple-1.0.tar.gz")
+        url = shared_data.packages.joinpath("simple-1.0.tar.gz").as_uri()
         hash = "sha256=ad977496000576e1b6c41f6449a9897087ce9da6db4f15b603fe8372af4bf3c6"
         finder = make_test_finder()
         wheel_cache = WheelCache(str(tmp_path / "cache"), FormatControl())
         cache_entry_dir = wheel_cache.get_path_for_link(Link(url))
-        Path(cache_entry_dir).mkdir(parents=True)
-        Path(cache_entry_dir).joinpath("origin.json").write_text(
+        pathlib.Path(cache_entry_dir).mkdir(parents=True)
+        pathlib.Path(cache_entry_dir).joinpath("origin.json").write_text(
             DirectUrl(url, ArchiveInfo(hash=hash)).to_json()
         )
         wheel.make_wheel(name="simple", version="1.0").save_to_dir(cache_entry_dir)
@@ -465,7 +466,7 @@ def test_download_info_local_dir(self, data: TestData) -> None:
         """Test that download_info is set for requirements from a local dir."""
         finder = make_test_finder()
         with self._basic_resolver(finder) as resolver:
-            ireq_url = path_to_url(data.packages / "FSPkg")
+            ireq_url = data.packages.joinpath("FSPkg").as_uri()
             ireq = get_processed_req_from_line(f"FSPkg @ {ireq_url}")
             reqset = resolver.resolve([ireq], True)
             assert len(reqset.all_requirements) == 1
@@ -478,7 +479,7 @@ def test_download_info_local_editable_dir(self, data: TestData) -> None:
         """Test that download_info is set for requirements from a local editable dir."""
         finder = make_test_finder()
         with self._basic_resolver(finder) as resolver:
-            ireq_url = path_to_url(data.packages / "FSPkg")
+            ireq_url = data.packages.joinpath("FSPkg").as_uri()
             ireq = get_processed_req_from_line(f"-e {ireq_url}#egg=FSPkg")
             reqset = resolver.resolve([ireq], True)
             assert len(reqset.all_requirements) == 1
@@ -909,9 +910,7 @@ def test_get_url_from_path__archive_file(
     isdir_mock.return_value = False
     isfile_mock.return_value = True
     name = "simple-0.1-py2.py3-none-any.whl"
-    path = os.path.join("/path/to/" + name)
-    url = path_to_url(path)
-    assert _get_url_from_path(path, name) == url
+    assert _get_url_from_path(f"/path/to/{name}", name) == f"file:///path/to/{name}"
 
 
 @mock.patch("pip._internal.req.req_install.os.path.isdir")
@@ -922,9 +921,7 @@ def test_get_url_from_path__installable_dir(
     isdir_mock.return_value = True
     isfile_mock.return_value = True
     name = "some/setuptools/project"
-    path = os.path.join("/path/to/" + name)
-    url = path_to_url(path)
-    assert _get_url_from_path(path, name) == url
+    assert _get_url_from_path(f"/path/to/{name}", name) == f"file:///path/to/{name}"
 
 
 @mock.patch("pip._internal.req.req_install.os.path.isdir")
diff --git a/tests/unit/test_req_file.py b/tests/unit/test_req_file.py
index 491877fb973..036dd409ebb 100644
--- a/tests/unit/test_req_file.py
+++ b/tests/unit/test_req_file.py
@@ -5,7 +5,7 @@
 import subprocess
 import textwrap
 from optparse import Values
-from typing import TYPE_CHECKING, Any, Iterator, List, Optional, Tuple
+from typing import TYPE_CHECKING, Any, Iterator, List, Optional, Tuple, Union
 from unittest import mock
 
 import pytest
@@ -29,7 +29,6 @@
 )
 from pip._internal.req.req_install import InstallRequirement
 from tests.lib import TestData, make_test_finder, requirements_file
-from tests.lib.path import Path
 
 if TYPE_CHECKING:
     from typing import Protocol
@@ -59,7 +58,7 @@ def options(session: PipSession) -> mock.Mock:
 
 
 def parse_reqfile(
-    filename: str,
+    filename: Union[pathlib.Path, str],
     session: PipSession,
     finder: PackageFinder = None,
     options: Values = None,
@@ -69,7 +68,7 @@ def parse_reqfile(
     # Wrap parse_requirements/install_req_from_parsed_requirement to
     # avoid having to write the same chunk of code in lots of tests.
     for parsed_req in parse_requirements(
-        filename,
+        str(filename),
         session,
         finder=finder,
         options=options,
@@ -203,7 +202,10 @@ def __call__(
 
 
 @pytest.fixture
-def line_processor(monkeypatch: pytest.MonkeyPatch, tmpdir: Path) -> LineProcessor:
+def line_processor(
+    monkeypatch: pytest.MonkeyPatch,
+    tmp_path: pathlib.Path,
+) -> LineProcessor:
     def process_line(
         line: str,
         filename: str,
@@ -217,10 +219,10 @@ def process_line(
             session = PipSession()
 
         prefix = "\n" * (line_number - 1)
-        path = tmpdir.joinpath(filename)
+        path = tmp_path.joinpath(filename)
         path.parent.mkdir(exist_ok=True)
         path.write_text(prefix + line)
-        monkeypatch.chdir(str(tmpdir))
+        monkeypatch.chdir(str(tmp_path))
         return list(
             parse_reqfile(
                 filename,
@@ -329,15 +331,18 @@ def test_yield_editable_constraint(self, line_processor: LineProcessor) -> None:
         assert found_req.constraint is True
 
     def test_nested_constraints_file(
-        self, monkeypatch: pytest.MonkeyPatch, tmpdir: Path, session: PipSession
+        self,
+        monkeypatch: pytest.MonkeyPatch,
+        tmp_path: pathlib.Path,
+        session: PipSession,
     ) -> None:
         req_name = "hello"
-        req_file = tmpdir / "parent" / "req_file.txt"
+        req_file = tmp_path.joinpath("parent", "req_file.txt")
         req_file.parent.mkdir()
         req_file.write_text("-c reqs.txt")
         req_file.parent.joinpath("reqs.txt").write_text(req_name)
 
-        monkeypatch.chdir(str(tmpdir))
+        monkeypatch.chdir(str(tmp_path))
 
         reqs = list(parse_reqfile("./parent/req_file.txt", session=session))
         assert len(reqs) == 1
@@ -461,14 +466,14 @@ def test_relative_local_find_links(
         line_processor: LineProcessor,
         finder: PackageFinder,
         monkeypatch: pytest.MonkeyPatch,
-        tmpdir: Path,
+        tmp_path: pathlib.Path,
     ) -> None:
         """
         Test a relative find_links path is joined with the req file directory
         """
-        base_path = tmpdir / "path"
+        base_path = tmp_path / "path"
 
-        def normalize(path: Path) -> str:
+        def normalize(path: pathlib.Path) -> str:
             return os.path.normcase(os.path.abspath(os.path.normpath(str(path))))
 
         # Make sure the test also passes on windows
@@ -517,18 +522,21 @@ def get_file_content(
         assert not result[0].constraint
 
     def test_relative_local_nested_req_files(
-        self, session: PipSession, monkeypatch: pytest.MonkeyPatch, tmpdir: Path
+        self,
+        session: PipSession,
+        monkeypatch: pytest.MonkeyPatch,
+        tmp_path: pathlib.Path,
     ) -> None:
         """
         Test a relative nested req file path is joined with the req file dir
         """
         req_name = "hello"
-        req_file = tmpdir / "parent" / "req_file.txt"
+        req_file = tmp_path.joinpath("parent", "req_file.txt")
         req_file.parent.mkdir()
         req_file.write_text("-r reqs.txt")
         req_file.parent.joinpath("reqs.txt").write_text(req_name)
 
-        monkeypatch.chdir(str(tmpdir))
+        monkeypatch.chdir(str(tmp_path))
 
         reqs = list(parse_reqfile("./parent/req_file.txt", session=session))
         assert len(reqs) == 1
@@ -536,15 +544,15 @@ def test_relative_local_nested_req_files(
         assert not reqs[0].constraint
 
     def test_absolute_local_nested_req_files(
-        self, session: PipSession, tmpdir: Path
+        self, session: PipSession, tmp_path: pathlib.Path
     ) -> None:
         """
         Test an absolute nested req file path
         """
         req_name = "hello"
-        req_file = tmpdir / "parent" / "req_file.txt"
+        req_file = tmp_path.joinpath("parent", "req_file.txt")
         req_file.parent.mkdir()
-        other_req_file = tmpdir / "other" / "reqs.txt"
+        other_req_file = tmp_path.joinpath("other", "reqs.txt")
         other_req_file.parent.mkdir()
         # POSIX-ify the path, since Windows backslashes aren't supported.
         other_req_file_str = str(other_req_file).replace("\\", "/")
@@ -552,19 +560,22 @@ def test_absolute_local_nested_req_files(
         req_file.write_text(f"-r {other_req_file_str}")
         other_req_file.write_text(req_name)
 
-        reqs = list(parse_reqfile(str(req_file), session=session))
+        reqs = list(parse_reqfile(req_file, session=session))
         assert len(reqs) == 1
         assert reqs[0].name == req_name
         assert not reqs[0].constraint
 
     def test_absolute_http_nested_req_file_in_local(
-        self, session: PipSession, monkeypatch: pytest.MonkeyPatch, tmpdir: Path
+        self,
+        session: PipSession,
+        monkeypatch: pytest.MonkeyPatch,
+        tmp_path: pathlib.Path,
     ) -> None:
         """
         Test a nested req file url in a local req file
         """
         req_name = "hello"
-        req_file = tmpdir / "req_file.txt"
+        req_file = tmp_path / "req_file.txt"
         nested_req_file = "http://me.com/me/req_file.txt"
 
         def get_file_content(
@@ -656,15 +667,15 @@ def test_remote_reqs_parse(self) -> None:
             pass
 
     def test_multiple_appending_options(
-        self, tmpdir: Path, finder: PackageFinder, options: mock.Mock
+        self, tmp_path: pathlib.Path, finder: PackageFinder, options: mock.Mock
     ) -> None:
-        with open(tmpdir.joinpath("req1.txt"), "w") as fp:
+        with tmp_path.joinpath("req1.txt").open("w") as fp:
             fp.write("--extra-index-url url1 \n")
             fp.write("--extra-index-url url2 ")
 
         list(
             parse_reqfile(
-                tmpdir.joinpath("req1.txt"),
+                tmp_path.joinpath("req1.txt"),
                 finder=finder,
                 session=PipSession(),
                 options=options,
@@ -674,7 +685,7 @@ def test_multiple_appending_options(
         assert finder.index_urls == ["url1", "url2"]
 
     def test_expand_existing_env_variables(
-        self, tmpdir: Path, finder: PackageFinder
+        self, tmp_path: pathlib.Path, finder: PackageFinder
     ) -> None:
         template = "https://{}:x-oauth-basic@github.com/user/{}/archive/master.zip"
 
@@ -688,7 +699,7 @@ def make_var(name: str) -> str:
             ]
         )
 
-        with open(tmpdir.joinpath("req1.txt"), "w") as fp:
+        with tmp_path.joinpath("req1.txt").open("w") as fp:
             fp.write(template.format(*map(make_var, env_vars)))
 
         # Construct the session outside the monkey-patch, since it access the
@@ -699,7 +710,7 @@ def make_var(name: str) -> str:
 
             reqs = list(
                 parse_reqfile(
-                    tmpdir.joinpath("req1.txt"), finder=finder, session=session
+                    tmp_path.joinpath("req1.txt"), finder=finder, session=session
                 )
             )
 
@@ -710,14 +721,14 @@ def make_var(name: str) -> str:
         assert reqs[0].link.url == expected_url, "variable expansion in req file failed"
 
     def test_expand_missing_env_variables(
-        self, tmpdir: Path, finder: PackageFinder
+        self, tmp_path: pathlib.Path, finder: PackageFinder
     ) -> None:
         req_url = (
             "https://${NON_EXISTENT_VARIABLE}:$WRONG_FORMAT@"
             "%WINDOWS_FORMAT%github.com/user/repo/archive/master.zip"
         )
 
-        with open(tmpdir.joinpath("req1.txt"), "w") as fp:
+        with tmp_path.joinpath("req1.txt").open("w") as fp:
             fp.write(req_url)
 
         # Construct the session outside the monkey-patch, since it access the
@@ -728,7 +739,7 @@ def test_expand_missing_env_variables(
 
             reqs = list(
                 parse_reqfile(
-                    tmpdir.joinpath("req1.txt"), finder=finder, session=session
+                    tmp_path.joinpath("req1.txt"), finder=finder, session=session
                 )
             )
 
@@ -738,13 +749,13 @@ def test_expand_missing_env_variables(
                 reqs[0].link.url == req_url
             ), "ignoring invalid env variable in req file failed"
 
-    def test_join_lines(self, tmpdir: Path, finder: PackageFinder) -> None:
-        with open(tmpdir.joinpath("req1.txt"), "w") as fp:
+    def test_join_lines(self, tmp_path: pathlib.Path, finder: PackageFinder) -> None:
+        with tmp_path.joinpath("req1.txt").open("w") as fp:
             fp.write("--extra-index-url url1 \\\n--extra-index-url url2")
 
         list(
             parse_reqfile(
-                tmpdir.joinpath("req1.txt"), finder=finder, session=PipSession()
+                tmp_path.joinpath("req1.txt"), finder=finder, session=PipSession()
             )
         )
 
@@ -764,34 +775,36 @@ def test_req_file_parse_no_only_binary(
         assert finder.format_control == expected
 
     def test_req_file_parse_comment_start_of_line(
-        self, tmpdir: Path, finder: PackageFinder
+        self, tmp_path: pathlib.Path, finder: PackageFinder
     ) -> None:
         """
         Test parsing comments in a requirements file
         """
-        with open(tmpdir.joinpath("req1.txt"), "w") as fp:
+        with tmp_path.joinpath("req1.txt").open("w") as fp:
             fp.write("# Comment ")
 
         reqs = list(
             parse_reqfile(
-                tmpdir.joinpath("req1.txt"), finder=finder, session=PipSession()
+                tmp_path.joinpath("req1.txt"), finder=finder, session=PipSession()
             )
         )
 
         assert not reqs
 
     def test_req_file_parse_comment_end_of_line_with_url(
-        self, tmpdir: Path, finder: PackageFinder
+        self, tmp_path: pathlib.Path, finder: PackageFinder
     ) -> None:
         """
         Test parsing comments in a requirements file
         """
-        with open(tmpdir.joinpath("req1.txt"), "w") as fp:
+        with tmp_path.joinpath("req1.txt").open("w") as fp:
             fp.write("https://example.com/foo.tar.gz # Comment ")
 
         reqs = list(
             parse_reqfile(
-                tmpdir.joinpath("req1.txt"), finder=finder, session=PipSession()
+                tmp_path.joinpath("req1.txt"),
+                finder=finder,
+                session=PipSession(),
             )
         )
 
@@ -800,28 +813,30 @@ def test_req_file_parse_comment_end_of_line_with_url(
         assert reqs[0].link.url == "https://example.com/foo.tar.gz"
 
     def test_req_file_parse_egginfo_end_of_line_with_url(
-        self, tmpdir: Path, finder: PackageFinder
+        self, tmp_path: pathlib.Path, finder: PackageFinder
     ) -> None:
         """
         Test parsing comments in a requirements file
         """
-        with open(tmpdir.joinpath("req1.txt"), "w") as fp:
+        with tmp_path.joinpath("req1.txt").open("w") as fp:
             fp.write("https://example.com/foo.tar.gz#egg=wat")
 
         reqs = list(
             parse_reqfile(
-                tmpdir.joinpath("req1.txt"), finder=finder, session=PipSession()
+                tmp_path.joinpath("req1.txt"),
+                finder=finder,
+                session=PipSession(),
             )
         )
 
         assert len(reqs) == 1
         assert reqs[0].name == "wat"
 
-    def test_req_file_no_finder(self, tmpdir: Path) -> None:
+    def test_req_file_no_finder(self, tmp_path: pathlib.Path) -> None:
         """
         Test parsing a requirements file without a finder
         """
-        with open(tmpdir.joinpath("req.txt"), "w") as fp:
+        with tmp_path.joinpath("req.txt").open("w") as fp:
             fp.write(
                 """
     --find-links https://example.com/
@@ -832,11 +847,11 @@ def test_req_file_no_finder(self, tmpdir: Path) -> None:
             """
             )
 
-        parse_reqfile(tmpdir.joinpath("req.txt"), session=PipSession())
+        parse_reqfile(tmp_path.joinpath("req.txt"), session=PipSession())
 
     def test_install_requirements_with_options(
         self,
-        tmpdir: Path,
+        tmp_path: pathlib.Path,
         finder: PackageFinder,
         session: PipSession,
         options: mock.Mock,
@@ -844,18 +859,19 @@ def test_install_requirements_with_options(
         global_option = "--dry-run"
         install_option = "--prefix=/opt"
 
-        content = """
+        content = f"""
         --only-binary :all:
         INITools==2.0 --global-option="{global_option}" \
                         --install-option "{install_option}"
-        """.format(
-            global_option=global_option, install_option=install_option
-        )
+        """
 
-        with requirements_file(content, tmpdir) as reqs_file:
+        with requirements_file(content, tmp_path) as reqs_file:
             req = next(
                 parse_reqfile(
-                    reqs_file.resolve(), finder=finder, options=options, session=session
+                    reqs_file.resolve(),
+                    finder=finder,
+                    options=options,
+                    session=session,
                 )
             )
 
diff --git a/tests/unit/test_req_install.py b/tests/unit/test_req_install.py
index ac2c0cdbb89..3991841a2a8 100644
--- a/tests/unit/test_req_install.py
+++ b/tests/unit/test_req_install.py
@@ -1,4 +1,5 @@
 import os
+import pathlib
 import tempfile
 
 import pytest
@@ -10,7 +11,6 @@
     install_req_from_req_string,
 )
 from pip._internal.req.req_install import InstallRequirement
-from tests.lib.path import Path
 
 
 class TestInstallRequirementBuildDirectory:
@@ -37,18 +37,15 @@ def test_tmp_build_directory(self) -> None:
         os.rmdir(tmp_dir)
         assert not os.path.exists(tmp_dir)
 
-    def test_forward_slash_results_in_a_link(self, tmpdir: Path) -> None:
-        install_dir = tmpdir / "foo" / "bar"
+    def test_forward_slash_results_in_a_link(self, tmp_path: pathlib.Path) -> None:
+        install_dir = tmp_path / "foo" / "bar"
+        install_dir.mkdir(parents=True)
 
         # Just create a file for letting the logic work
         setup_py_path = install_dir / "setup.py"
-        os.makedirs(str(install_dir))
-        with open(setup_py_path, "w") as f:
-            f.write("")
+        setup_py_path.touch()
 
-        requirement = install_req_from_line(
-            str(install_dir).replace(os.sep, os.altsep or os.sep)
-        )
+        requirement = install_req_from_line(install_dir.as_posix())
 
         assert requirement.link is not None
 
diff --git a/tests/unit/test_req_uninstall.py b/tests/unit/test_req_uninstall.py
index b3049e1037c..801385ba53e 100644
--- a/tests/unit/test_req_uninstall.py
+++ b/tests/unit/test_req_uninstall.py
@@ -1,4 +1,5 @@
 import os
+import pathlib
 import sys
 from typing import Iterator, List, Optional, Tuple
 from unittest.mock import Mock
@@ -16,7 +17,6 @@
     uninstallation_paths,
 )
 from tests.lib import create_file
-from tests.lib.path import Path
 
 
 # Pretend all files are local, so UninstallPathSet accepts files in the tmpdir,
@@ -57,12 +57,12 @@ def iter_declared_entries(self) -> Optional[Iterator[str]]:
     assert paths2 == paths
 
 
-def test_compressed_listing(tmpdir: Path) -> None:
+def test_compressed_listing(tmp_path: pathlib.Path) -> None:
     def in_tmpdir(paths: List[str]) -> List[str]:
-        li = []
-        for path in paths:
-            li.append(str(os.path.join(tmpdir, path.replace("/", os.path.sep))))
-        return li
+        return [
+            str(os.path.join(tmp_path, path.replace("/", os.path.sep)))
+            for path in paths
+        ]
 
     sample = in_tmpdir(
         [
@@ -128,11 +128,11 @@ def in_tmpdir(paths: List[str]) -> List[str]:
 
 
 class TestUninstallPathSet:
-    def test_add(self, tmpdir: Path, monkeypatch: pytest.MonkeyPatch) -> None:
+    def test_add(self, tmp_path: pathlib.Path, monkeypatch: pytest.MonkeyPatch) -> None:
         monkeypatch.setattr(pip._internal.req.req_uninstall, "is_local", mock_is_local)
         # Fix case for windows tests
-        file_extant = os.path.normcase(os.path.join(tmpdir, "foo"))
-        file_nonexistent = os.path.normcase(os.path.join(tmpdir, "nonexistent"))
+        file_extant = os.path.normcase(os.path.join(tmp_path, "foo"))
+        file_nonexistent = os.path.normcase(os.path.join(tmp_path, "nonexistent"))
         with open(file_extant, "w"):
             pass
 
@@ -144,42 +144,49 @@ def test_add(self, tmpdir: Path, monkeypatch: pytest.MonkeyPatch) -> None:
         ups.add(file_nonexistent)
         assert ups._paths == {file_extant}
 
-    def test_add_pth(self, tmpdir: str, monkeypatch: pytest.MonkeyPatch) -> None:
+    def test_add_pth(
+        self,
+        tmp_path: pathlib.Path,
+        monkeypatch: pytest.MonkeyPatch,
+    ) -> None:
         monkeypatch.setattr(pip._internal.req.req_uninstall, "is_local", mock_is_local)
         # Fix case for windows tests
-        tmpdir = os.path.normcase(tmpdir)
         on_windows = sys.platform == "win32"
-        pth_file = os.path.join(tmpdir, "foo.pth")
+        pth_file = os.path.join(tmp_path, "foo.pth")
         relative = "../../example"
         if on_windows:
             share = "\\\\example\\share\\"
             share_com = "\\\\example.com\\share\\"
         # Create a .pth file for testing
         with open(pth_file, "w") as f:
-            f.writelines([tmpdir, "\n", relative, "\n"])
+            f.writelines([str(tmp_path), "\n", relative, "\n"])
             if on_windows:
                 f.writelines([share, "\n", share_com, "\n"])
         # Add paths to be removed
         pth = UninstallPthEntries(pth_file)
-        pth.add(tmpdir)
+        pth.add(str(tmp_path))
         pth.add(relative)
         if on_windows:
             pth.add(share)
             pth.add(share_com)
         # Check that the paths were added to entries
         if on_windows:
-            check = {tmpdir, relative, share, share_com}
+            check = {str(tmp_path), relative, share, share_com}
         else:
-            check = {tmpdir, relative}
+            check = {str(tmp_path), relative}
         assert pth.entries == check
 
     @pytest.mark.skipif("sys.platform == 'win32'")
-    def test_add_symlink(self, tmpdir: Path, monkeypatch: pytest.MonkeyPatch) -> None:
+    def test_add_symlink(
+        self,
+        tmp_path: pathlib.Path,
+        monkeypatch: pytest.MonkeyPatch,
+    ) -> None:
         monkeypatch.setattr(pip._internal.req.req_uninstall, "is_local", mock_is_local)
-        f = os.path.join(tmpdir, "foo")
+        f = os.path.join(tmp_path, "foo")
         with open(f, "w"):
             pass
-        foo_link = os.path.join(tmpdir, "foo_link")
+        foo_link = os.path.join(tmp_path, "foo_link")
         os.symlink(f, foo_link)
 
         ups = UninstallPathSet(dist=Mock())
@@ -200,16 +207,16 @@ def test_compact_shorter_path(self, monkeypatch: pytest.MonkeyPatch) -> None:
 
     @pytest.mark.skipif("sys.platform == 'win32'")
     def test_detect_symlink_dirs(
-        self, monkeypatch: pytest.MonkeyPatch, tmpdir: Path
+        self, monkeypatch: pytest.MonkeyPatch, tmp_path: pathlib.Path
     ) -> None:
         monkeypatch.setattr(pip._internal.req.req_uninstall, "is_local", mock_is_local)
 
         # construct 2 paths:
         #  tmpdir/dir/file
         #  tmpdir/dirlink/file (where dirlink is a link to dir)
-        d = tmpdir.joinpath("dir")
+        d = tmp_path.joinpath("dir")
         d.mkdir()
-        dlink = tmpdir.joinpath("dirlink")
+        dlink = tmp_path.joinpath("dirlink")
         os.symlink(d, dlink)
         d.joinpath("file").touch()
         path1 = str(d.joinpath("file"))
@@ -269,10 +276,10 @@ def test_compress_for_rename(self, monkeypatch: pytest.MonkeyPatch) -> None:
 
     @classmethod
     def make_stash(
-        cls, tmpdir: Path, paths: List[str]
+        cls, tmp_path: pathlib.Path, paths: List[str]
     ) -> Tuple[StashedUninstallPathSet, List[Tuple[str, str]]]:
         for dirname, subdirs, files in cls.WALK_RESULT:
-            root = os.path.join(tmpdir, *dirname.split("/"))
+            root = os.path.join(tmp_path, *dirname.split("/"))
             if not os.path.exists(root):
                 os.mkdir(root)
             for d in subdirs:
@@ -283,14 +290,14 @@ def make_stash(
 
         pathset = StashedUninstallPathSet()
 
-        paths = [os.path.join(tmpdir, *p.split("/")) for p in paths]
+        paths = [os.path.join(tmp_path, *p.split("/")) for p in paths]
         stashed_paths = [(p, pathset.stash(p)) for p in paths]
 
         return pathset, stashed_paths
 
-    def test_stash(self, tmpdir: Path) -> None:
+    def test_stash(self, tmp_path: pathlib.Path) -> None:
         pathset, stashed_paths = self.make_stash(
-            tmpdir,
+            tmp_path,
             [
                 "A/B/",
                 "A/C/d.py",
@@ -305,9 +312,9 @@ def test_stash(self, tmpdir: Path) -> None:
 
         assert stashed_paths == pathset._moves
 
-    def test_commit(self, tmpdir: Path) -> None:
+    def test_commit(self, tmp_path: pathlib.Path) -> None:
         pathset, stashed_paths = self.make_stash(
-            tmpdir,
+            tmp_path,
             [
                 "A/B/",
                 "A/C/d.py",
@@ -322,9 +329,9 @@ def test_commit(self, tmpdir: Path) -> None:
             assert not os.path.exists(old_path)
             assert not os.path.exists(new_path)
 
-    def test_rollback(self, tmpdir: Path) -> None:
+    def test_rollback(self, tmp_path: pathlib.Path) -> None:
         pathset, stashed_paths = self.make_stash(
-            tmpdir,
+            tmp_path,
             [
                 "A/B/",
                 "A/C/d.py",
@@ -340,20 +347,20 @@ def test_rollback(self, tmpdir: Path) -> None:
             assert not os.path.exists(new_path)
 
     @pytest.mark.skipif("sys.platform == 'win32'")
-    def test_commit_symlinks(self, tmpdir: Path) -> None:
-        adir = tmpdir / "dir"
+    def test_commit_symlinks(self, tmp_path: pathlib.Path) -> None:
+        adir = tmp_path / "dir"
         adir.mkdir()
-        dirlink = tmpdir / "dirlink"
+        dirlink = tmp_path / "dirlink"
         dirlink.symlink_to(adir)
-        afile = tmpdir / "file"
+        afile = tmp_path / "file"
         afile.write_text("...")
-        filelink = tmpdir / "filelink"
+        filelink = tmp_path / "filelink"
         filelink.symlink_to(afile)
 
         pathset = StashedUninstallPathSet()
         stashed_paths = []
-        stashed_paths.append(pathset.stash(dirlink))
-        stashed_paths.append(pathset.stash(filelink))
+        stashed_paths.append(pathset.stash(str(dirlink)))
+        stashed_paths.append(pathset.stash(str(filelink)))
         for stashed_path in stashed_paths:
             assert os.path.lexists(stashed_path)
         assert not os.path.exists(dirlink)
@@ -372,20 +379,20 @@ def test_commit_symlinks(self, tmpdir: Path) -> None:
         assert os.path.isfile(afile)
 
     @pytest.mark.skipif("sys.platform == 'win32'")
-    def test_rollback_symlinks(self, tmpdir: Path) -> None:
-        adir = tmpdir / "dir"
+    def test_rollback_symlinks(self, tmp_path: pathlib.Path) -> None:
+        adir = tmp_path / "dir"
         adir.mkdir()
-        dirlink = tmpdir / "dirlink"
+        dirlink = tmp_path / "dirlink"
         dirlink.symlink_to(adir)
-        afile = tmpdir / "file"
+        afile = tmp_path / "file"
         afile.write_text("...")
-        filelink = tmpdir / "filelink"
+        filelink = tmp_path / "filelink"
         filelink.symlink_to(afile)
 
         pathset = StashedUninstallPathSet()
         stashed_paths = []
-        stashed_paths.append(pathset.stash(dirlink))
-        stashed_paths.append(pathset.stash(filelink))
+        stashed_paths.append(pathset.stash(str(dirlink)))
+        stashed_paths.append(pathset.stash(str(filelink)))
         for stashed_path in stashed_paths:
             assert os.path.lexists(stashed_path)
         assert not os.path.lexists(dirlink)
diff --git a/tests/unit/test_resolution_legacy_resolver.py b/tests/unit/test_resolution_legacy_resolver.py
index 134ff65b498..809eb15a9ab 100644
--- a/tests/unit/test_resolution_legacy_resolver.py
+++ b/tests/unit/test_resolution_legacy_resolver.py
@@ -110,7 +110,7 @@ def test_unsupported_wheel_local_file_requirement_raises(
         requirement_set = RequirementSet(check_supported_wheels=True)
 
         install_req = install_req_from_line(
-            data.packages.joinpath("simple.dist-0.1-py1-none-invalid.whl"),
+            str(data.packages.joinpath("simple.dist-0.1-py1-none-invalid.whl")),
         )
         assert install_req.link is not None
         assert install_req.link.is_wheel
diff --git a/tests/unit/test_self_check_outdated.py b/tests/unit/test_self_check_outdated.py
index edfc4e82f19..7194986f5e1 100644
--- a/tests/unit/test_self_check_outdated.py
+++ b/tests/unit/test_self_check_outdated.py
@@ -1,6 +1,7 @@
 import datetime
 import json
 import logging
+import pathlib
 import sys
 from optparse import Values
 from typing import Optional
@@ -11,7 +12,6 @@
 from pip._vendor.packaging.version import Version
 
 from pip._internal import self_outdated_check
-from tests.lib.path import Path
 
 
 @pytest.mark.parametrize(
@@ -35,19 +35,19 @@ def test_get_statefile_name_known_values(key: str, expected: str) -> None:
 @patch("pip._internal.self_outdated_check._self_version_check_logic")
 @patch("pip._internal.self_outdated_check.SelfCheckState")
 def test_pip_self_version_check_calls_underlying_implementation(
-    mocked_state: Mock, mocked_function: Mock, tmpdir: Path
+    mocked_state: Mock, mocked_function: Mock, tmp_path: pathlib.Path
 ) -> None:
     # GIVEN
     mock_session = Mock()
-    fake_options = Values(dict(cache_dir=str(tmpdir)))
+    fake_options = Values({"cache_dir": str(tmp_path)})
 
     # WHEN
     self_outdated_check.pip_self_version_check(mock_session, fake_options)
 
     # THEN
-    mocked_state.assert_called_once_with(cache_dir=str(tmpdir))
+    mocked_state.assert_called_once_with(cache_dir=str(tmp_path))
     mocked_function.assert_called_once_with(
-        state=mocked_state(cache_dir=str(tmpdir)),
+        state=mocked_state(cache_dir=str(tmp_path)),
         current_time=datetime.datetime(1970, 1, 2, 11, 0, 0),
         local_version=ANY,
         get_remote_version=ANY,
@@ -134,9 +134,9 @@ def test_no_cache(self) -> None:
         state = self_outdated_check.SelfCheckState(cache_dir="")
         assert state._statefile_path is None
 
-    def test_reads_expected_statefile(self, tmpdir: Path) -> None:
+    def test_reads_expected_statefile(self, tmp_path: pathlib.Path) -> None:
         # GIVEN
-        cache_dir = tmpdir / "cache_dir"
+        cache_dir = tmp_path / "cache_dir"
         expected_path = (
             cache_dir
             / "selfcheck"
@@ -151,12 +151,12 @@ def test_reads_expected_statefile(self, tmpdir: Path) -> None:
         state = self_outdated_check.SelfCheckState(cache_dir=str(cache_dir))
 
         # THEN
-        assert state._statefile_path == expected_path
+        assert state._statefile_path == str(expected_path)
         assert state._state == {"foo": "bar"}
 
-    def test_writes_expected_statefile(self, tmpdir: Path) -> None:
+    def test_writes_expected_statefile(self, tmp_path: pathlib.Path) -> None:
         # GIVEN
-        cache_dir = tmpdir / "cache_dir"
+        cache_dir = tmp_path / "cache_dir"
         cache_dir.mkdir()
         expected_path = (
             cache_dir
@@ -169,7 +169,7 @@ def test_writes_expected_statefile(self, tmpdir: Path) -> None:
         state.set("1.0.0", datetime.datetime(2000, 1, 1, 0, 0, 0))
 
         # THEN
-        assert state._statefile_path == expected_path
+        assert state._statefile_path == str(expected_path)
 
         contents = expected_path.read_text()
         assert json.loads(contents) == {
diff --git a/tests/unit/test_utils.py b/tests/unit/test_utils.py
index 2d0a82bddf7..7afafacea00 100644
--- a/tests/unit/test_utils.py
+++ b/tests/unit/test_utils.py
@@ -4,6 +4,7 @@
 """
 import codecs
 import os
+import pathlib
 import shutil
 import stat
 import sys
@@ -46,7 +47,6 @@
     tabulate,
 )
 from pip._internal.utils.setuptools_build import make_setuptools_shim_args
-from tests.lib.path import Path
 
 
 class Tests_EgglinkPath:
@@ -207,11 +207,11 @@ def test_noegglink_in_sitepkgs_venv_global(self) -> None:
         assert egg_link_path_from_location(self.mock_dist.project_name) is None
 
 
-def test_rmtree_errorhandler_nonexistent_directory(tmpdir: Path) -> None:
+def test_rmtree_errorhandler_nonexistent_directory(tmp_path: pathlib.Path) -> None:
     """
     Test rmtree_errorhandler ignores the given non-existing directory.
     """
-    nonexistent_path = str(tmpdir / "foo")
+    nonexistent_path = str(tmp_path / "foo")
     mock_func = Mock()
     # Argument 3 to "rmtree_errorhandler" has incompatible type "None"; expected
     # "Tuple[Type[BaseException], BaseException, TracebackType]"
@@ -219,12 +219,12 @@ def test_rmtree_errorhandler_nonexistent_directory(tmpdir: Path) -> None:
     mock_func.assert_not_called()
 
 
-def test_rmtree_errorhandler_readonly_directory(tmpdir: Path) -> None:
+def test_rmtree_errorhandler_readonly_directory(tmp_path: pathlib.Path) -> None:
     """
     Test rmtree_errorhandler makes the given read-only directory writable.
     """
     # Create read only directory
-    subdir_path = tmpdir / "subdir"
+    subdir_path = tmp_path / "subdir"
     subdir_path.mkdir()
     path = str(subdir_path)
     os.chmod(path, stat.S_IREAD)
@@ -240,13 +240,13 @@ def test_rmtree_errorhandler_readonly_directory(tmpdir: Path) -> None:
     assert os.stat(path).st_mode & stat.S_IWRITE
 
 
-def test_rmtree_errorhandler_reraises_error(tmpdir: Path) -> None:
+def test_rmtree_errorhandler_reraises_error(tmp_path: pathlib.Path) -> None:
     """
     Test rmtree_errorhandler reraises an exception
     by the given unreadable directory.
     """
     # Create directory without read permission
-    subdir_path = tmpdir / "subdir"
+    subdir_path = tmp_path / "subdir"
     subdir_path.mkdir()
     path = str(subdir_path)
     os.chmod(path, stat.S_IWRITE)
@@ -315,11 +315,9 @@ class Test_normalize_path:
     # permission bit to create them, and Python 2 doesn't support it anyway, so
     # it's easiest just to skip this test on Windows altogether.
     @pytest.mark.skipif("sys.platform == 'win32'")
-    def test_resolve_symlinks(self, tmpdir: Path) -> None:
-        print(type(tmpdir))
-        print(dir(tmpdir))
+    def test_resolve_symlinks(self, tmp_path: pathlib.Path) -> None:
         orig_working_dir = os.getcwd()
-        os.chdir(tmpdir)
+        os.chdir(tmp_path)
         try:
             d = os.path.join("foo", "bar")
             f = os.path.join(d, "file1")
@@ -332,16 +330,16 @@ def test_resolve_symlinks(self, tmpdir: Path) -> None:
 
             assert normalize_path(
                 "dir_link/file1", resolve_symlinks=True
-            ) == os.path.join(tmpdir, f)
+            ) == os.path.join(tmp_path, f)
             assert normalize_path(
                 "dir_link/file1", resolve_symlinks=False
-            ) == os.path.join(tmpdir, "dir_link", "file1")
+            ) == os.path.join(tmp_path, "dir_link", "file1")
 
             assert normalize_path("file_link", resolve_symlinks=True) == os.path.join(
-                tmpdir, f
+                tmp_path, f
             )
             assert normalize_path("file_link", resolve_symlinks=False) == os.path.join(
-                tmpdir, "file_link"
+                tmp_path, "file_link"
             )
         finally:
             os.chdir(orig_working_dir)
@@ -371,13 +369,13 @@ def test_is_hash_allowed(
         hashes = Hashes(hashes_data)
         assert hashes.is_hash_allowed(hash_name, hex_digest) == expected
 
-    def test_success(self, tmpdir: Path) -> None:
+    def test_success(self, tmp_path: pathlib.Path) -> None:
         """Make sure no error is raised when at least one hash matches.
 
         Test check_against_path because it calls everything else.
 
         """
-        file = tmpdir / "to_hash"
+        file = tmp_path / "to_hash"
         file.write_text("hello")
         hashes = Hashes(
             {
@@ -389,7 +387,7 @@ def test_success(self, tmpdir: Path) -> None:
                 "md5": ["5d41402abc4b2a76b9719d911017c592"],
             }
         )
-        hashes.check_against_path(file)
+        hashes.check_against_path(str(file))
 
     def test_failure(self) -> None:
         """Hashes should raise HashMismatch when no hashes match."""
diff --git a/tests/unit/test_utils_filesystem.py b/tests/unit/test_utils_filesystem.py
index 1b730f8b8f7..c5fd90f2a24 100644
--- a/tests/unit/test_utils_filesystem.py
+++ b/tests/unit/test_utils_filesystem.py
@@ -1,16 +1,16 @@
 import os
+import pathlib
 
-from tests.lib.path import Path
 
-
-def make_file(path: str) -> None:
-    Path(path).touch()
+def make_file(path: str) -> pathlib.Path:
+    p = pathlib.Path(path)
+    p.touch()
+    return p
 
 
 def make_valid_symlink(path: str) -> None:
-    target = path + "1"
-    make_file(target)
-    os.symlink(target, path)
+    target = make_file(path + "1")
+    target.symlink_to(path)
 
 
 def make_broken_symlink(path: str) -> None:
diff --git a/tests/unit/test_utils_temp_dir.py b/tests/unit/test_utils_temp_dir.py
index 6b3571ff71c..2059f767cba 100644
--- a/tests/unit/test_utils_temp_dir.py
+++ b/tests/unit/test_utils_temp_dir.py
@@ -1,5 +1,6 @@
 import itertools
 import os
+import pathlib
 import stat
 import tempfile
 from typing import Any, Iterator, Optional, Union
@@ -16,7 +17,6 @@
     global_tempdir_manager,
     tempdir_registry,
 )
-from tests.lib.path import Path
 
 
 # No need to test symlinked directories on Windows
@@ -165,13 +165,13 @@ def names() -> Iterator[str]:
         "_package",
     ],
 )
-def test_adjacent_directory_exists(name: str, tmpdir: Path) -> None:
+def test_adjacent_directory_exists(name: str, tmp_path: pathlib.Path) -> None:
     block_name, expect_name = itertools.islice(
         AdjacentTempDirectory._generate_names(name), 2
     )
 
-    original = os.path.join(tmpdir, name)
-    blocker = os.path.join(tmpdir, block_name)
+    original = os.path.join(tmp_path, name)
+    blocker = os.path.join(tmp_path, block_name)
 
     ensure_dir(original)
     ensure_dir(blocker)
@@ -247,16 +247,16 @@ def test_tempdir_registry(
 
 @pytest.mark.parametrize("delete,exists", [(_default, True), (None, False)])
 def test_temp_dir_does_not_delete_explicit_paths_by_default(
-    tmpdir: Path, delete: Optional[_Default], exists: bool
+    tmp_path: pathlib.Path, delete: Optional[_Default], exists: bool
 ) -> None:
-    path = tmpdir / "example"
+    path = tmp_path / "example"
     path.mkdir()
 
     with tempdir_registry() as registry:
         registry.set_delete(deleted_kind, True)
 
-        with TempDirectory(path=path, delete=delete, kind=deleted_kind) as d:
-            assert str(d.path) == path
+        with TempDirectory(path=str(path), delete=delete, kind=deleted_kind) as d:
+            assert d.path == str(path)
             assert os.path.exists(path)
         assert os.path.exists(path) == exists
 
diff --git a/tests/unit/test_utils_unpacking.py b/tests/unit/test_utils_unpacking.py
index ccb7a304925..6d100c85b35 100644
--- a/tests/unit/test_utils_unpacking.py
+++ b/tests/unit/test_utils_unpacking.py
@@ -1,5 +1,6 @@
 import io
 import os
+import pathlib
 import shutil
 import stat
 import sys
@@ -14,7 +15,6 @@
 from pip._internal.exceptions import InstallationError
 from pip._internal.utils.unpacking import is_within_directory, untar_file, unzip_file
 from tests.lib import TestData
-from tests.lib.path import Path
 
 
 class TestUnpackArchives:
@@ -106,7 +106,7 @@ def test_unpack_tgz(self, data: TestData) -> None:
         Test unpacking a *.tgz, and setting execute permissions
         """
         test_file = data.packages.joinpath("test_tar.tgz")
-        untar_file(test_file, self.tempdir)
+        untar_file(str(test_file), self.tempdir)
         self.confirm_files()
         # Check the timestamp of an extracted file
         file_txt_path = os.path.join(self.tempdir, "file.txt")
@@ -118,7 +118,7 @@ def test_unpack_zip(self, data: TestData) -> None:
         Test unpacking a *.zip, and setting execute permissions
         """
         test_file = data.packages.joinpath("test_zip.zip")
-        unzip_file(test_file, self.tempdir)
+        unzip_file(str(test_file), self.tempdir)
         self.confirm_files()
 
     def test_unpack_zip_failure(self) -> None:
@@ -172,17 +172,17 @@ def test_unpack_tar_success(self) -> None:
         untar_file(test_tar, self.tempdir)
 
 
-def test_unpack_tar_unicode(tmpdir: Path) -> None:
-    test_tar = tmpdir / "test.tar"
+def test_unpack_tar_unicode(tmp_path: pathlib.Path) -> None:
+    test_tar = tmp_path / "test.tar"
     # tarfile tries to decode incoming
     with tarfile.open(test_tar, "w", format=tarfile.PAX_FORMAT, encoding="utf-8") as f:
         metadata = tarfile.TarInfo("dir/åäö_日本語.py")
         f.addfile(metadata, io.BytesIO(b"hello world"))
 
-    output_dir = tmpdir / "output"
+    output_dir = tmp_path / "output"
     output_dir.mkdir()
 
-    untar_file(test_tar, str(output_dir))
+    untar_file(str(test_tar), str(output_dir))
 
     output_dir_name = str(output_dir)
     contents = os.listdir(output_dir_name)
diff --git a/tests/unit/test_utils_virtualenv.py b/tests/unit/test_utils_virtualenv.py
index 8f517d24d36..e5540fcb2b1 100644
--- a/tests/unit/test_utils_virtualenv.py
+++ b/tests/unit/test_utils_virtualenv.py
@@ -1,4 +1,5 @@
 import logging
+import pathlib
 import site
 import sys
 from typing import List, Optional
@@ -6,7 +7,6 @@
 import pytest
 
 from pip._internal.utils import virtualenv
-from tests.lib.path import Path
 
 
 @pytest.mark.parametrize(
@@ -52,21 +52,21 @@ def test_running_under_virtualenv(
 )
 def test_virtualenv_no_global_with_regular_virtualenv(
     monkeypatch: pytest.MonkeyPatch,
-    tmpdir: Path,
+    tmp_path: pathlib.Path,
     under_virtualenv: bool,
     no_global_file: bool,
     expected: bool,
 ) -> None:
     monkeypatch.setattr(virtualenv, "_running_under_venv", lambda: False)
 
-    monkeypatch.setattr(site, "__file__", tmpdir / "site.py")
+    monkeypatch.setattr(site, "__file__", str(tmp_path / "site.py"))
     monkeypatch.setattr(
         virtualenv,
         "_running_under_regular_virtualenv",
         lambda: under_virtualenv,
     )
     if no_global_file:
-        (tmpdir / "no-global-site-packages.txt").touch()
+        (tmp_path / "no-global-site-packages.txt").touch()
 
     assert virtualenv.virtualenv_no_global() == expected
 
@@ -133,12 +133,12 @@ def test_virtualenv_no_global_with_pep_405_virtual_environment(
 )
 def test_get_pyvenv_cfg_lines_for_pep_405_virtual_environment(
     monkeypatch: pytest.MonkeyPatch,
-    tmpdir: Path,
+    tmp_path: pathlib.Path,
     contents: Optional[str],
     expected: Optional[List[str]],
 ) -> None:
-    monkeypatch.setattr(sys, "prefix", str(tmpdir))
+    monkeypatch.setattr(sys, "prefix", str(tmp_path))
     if contents is not None:
-        tmpdir.joinpath("pyvenv.cfg").write_text(contents)
+        tmp_path.joinpath("pyvenv.cfg").write_text(contents)
 
     assert virtualenv._get_pyvenv_cfg_lines() == expected
diff --git a/tests/unit/test_utils_wheel.py b/tests/unit/test_utils_wheel.py
index 53e149f9493..a4304c5cbba 100644
--- a/tests/unit/test_utils_wheel.py
+++ b/tests/unit/test_utils_wheel.py
@@ -1,4 +1,5 @@
 import os
+import pathlib
 from contextlib import ExitStack
 from email import message_from_string
 from io import BytesIO
@@ -10,14 +11,13 @@
 from pip._internal.exceptions import UnsupportedWheel
 from pip._internal.utils import wheel
 from tests.lib import TestData
-from tests.lib.path import Path
 
-_ZipDir = Callable[[Path], ZipFile]
+_ZipDir = Callable[[pathlib.Path], ZipFile]
 
 
 @pytest.fixture
 def zip_dir() -> Iterator[_ZipDir]:
-    def make_zip(path: Path) -> ZipFile:
+    def make_zip(path: pathlib.Path) -> ZipFile:
         buf = BytesIO()
         with ZipFile(buf, "w", allowZip64=True) as z:
             for dirpath, _, filenames in os.walk(path):
@@ -36,38 +36,41 @@ def make_zip(path: Path) -> ZipFile:
         yield make_zip
 
 
-def test_wheel_dist_info_dir_found(tmpdir: Path, zip_dir: _ZipDir) -> None:
+def test_wheel_dist_info_dir_found(tmp_path: pathlib.Path, zip_dir: _ZipDir) -> None:
     expected = "simple-0.1.dist-info"
-    dist_info_dir = tmpdir / expected
+    dist_info_dir = tmp_path / expected
     dist_info_dir.mkdir()
     dist_info_dir.joinpath("WHEEL").touch()
-    assert wheel.wheel_dist_info_dir(zip_dir(tmpdir), "simple") == expected
+    assert wheel.wheel_dist_info_dir(zip_dir(tmp_path), "simple") == expected
 
 
-def test_wheel_dist_info_dir_multiple(tmpdir: Path, zip_dir: _ZipDir) -> None:
-    dist_info_dir_1 = tmpdir / "simple-0.1.dist-info"
+def test_wheel_dist_info_dir_multiple(tmp_path: pathlib.Path, zip_dir: _ZipDir) -> None:
+    dist_info_dir_1 = tmp_path / "simple-0.1.dist-info"
     dist_info_dir_1.mkdir()
     dist_info_dir_1.joinpath("WHEEL").touch()
-    dist_info_dir_2 = tmpdir / "unrelated-0.1.dist-info"
+    dist_info_dir_2 = tmp_path / "unrelated-0.1.dist-info"
     dist_info_dir_2.mkdir()
     dist_info_dir_2.joinpath("WHEEL").touch()
     with pytest.raises(UnsupportedWheel) as e:
-        wheel.wheel_dist_info_dir(zip_dir(tmpdir), "simple")
+        wheel.wheel_dist_info_dir(zip_dir(tmp_path), "simple")
     assert "multiple .dist-info directories found" in str(e.value)
 
 
-def test_wheel_dist_info_dir_none(tmpdir: Path, zip_dir: _ZipDir) -> None:
+def test_wheel_dist_info_dir_none(tmp_path: pathlib.Path, zip_dir: _ZipDir) -> None:
     with pytest.raises(UnsupportedWheel) as e:
-        wheel.wheel_dist_info_dir(zip_dir(tmpdir), "simple")
+        wheel.wheel_dist_info_dir(zip_dir(tmp_path), "simple")
     assert "directory not found" in str(e.value)
 
 
-def test_wheel_dist_info_dir_wrong_name(tmpdir: Path, zip_dir: _ZipDir) -> None:
-    dist_info_dir = tmpdir / "unrelated-0.1.dist-info"
+def test_wheel_dist_info_dir_wrong_name(
+    tmp_path: pathlib.Path,
+    zip_dir: _ZipDir,
+) -> None:
+    dist_info_dir = tmp_path / "unrelated-0.1.dist-info"
     dist_info_dir.mkdir()
     dist_info_dir.joinpath("WHEEL").touch()
     with pytest.raises(UnsupportedWheel) as e:
-        wheel.wheel_dist_info_dir(zip_dir(tmpdir), "simple")
+        wheel.wheel_dist_info_dir(zip_dir(tmp_path), "simple")
     assert "does not start with 'simple'" in str(e.value)
 
 
@@ -75,24 +78,30 @@ def test_wheel_version_ok(data: TestData) -> None:
     assert wheel.wheel_version(message_from_string("Wheel-Version: 1.9")) == (1, 9)
 
 
-def test_wheel_metadata_fails_missing_wheel(tmpdir: Path, zip_dir: _ZipDir) -> None:
-    dist_info_dir = tmpdir / "simple-0.1.0.dist-info"
+def test_wheel_metadata_fails_missing_wheel(
+    tmp_path: pathlib.Path,
+    zip_dir: _ZipDir,
+) -> None:
+    dist_info_dir = tmp_path / "simple-0.1.0.dist-info"
     dist_info_dir.mkdir()
     dist_info_dir.joinpath("METADATA").touch()
 
     with pytest.raises(UnsupportedWheel) as e:
-        wheel.wheel_metadata(zip_dir(tmpdir), dist_info_dir.name)
+        wheel.wheel_metadata(zip_dir(tmp_path), dist_info_dir.name)
     assert "could not read" in str(e.value)
 
 
-def test_wheel_metadata_fails_on_bad_encoding(tmpdir: Path, zip_dir: _ZipDir) -> None:
-    dist_info_dir = tmpdir / "simple-0.1.0.dist-info"
+def test_wheel_metadata_fails_on_bad_encoding(
+    tmp_path: pathlib.Path,
+    zip_dir: _ZipDir,
+) -> None:
+    dist_info_dir = tmp_path / "simple-0.1.0.dist-info"
     dist_info_dir.mkdir()
     dist_info_dir.joinpath("METADATA").touch()
     dist_info_dir.joinpath("WHEEL").write_bytes(b"\xff")
 
     with pytest.raises(UnsupportedWheel) as e:
-        wheel.wheel_metadata(zip_dir(tmpdir), dist_info_dir.name)
+        wheel.wheel_metadata(zip_dir(tmp_path), dist_info_dir.name)
     assert "error decoding" in str(e.value)
 
 
diff --git a/tests/unit/test_vcs.py b/tests/unit/test_vcs.py
index 64f60bc407a..f98529cbfc7 100644
--- a/tests/unit/test_vcs.py
+++ b/tests/unit/test_vcs.py
@@ -15,7 +15,6 @@
 from pip._internal.vcs.subversion import Subversion
 from pip._internal.vcs.versioncontrol import RevOptions, VersionControl
 from tests.lib import is_svn_installed, need_svn
-from tests.lib.path import Path
 
 
 @pytest.mark.skipif(
@@ -201,8 +200,8 @@ def test_paths_are_not_mistaken_for_scp_shorthand(url: str, platform: str) -> No
             Git._git_remote_to_pip_url(url)
 
 
-def test_git_remote_local_path(tmpdir: Path) -> None:
-    path = pathlib.Path(tmpdir, "project.git")
+def test_git_remote_local_path(tmp_path: pathlib.Path) -> None:
+    path = tmp_path.joinpath("project.git")
     path.mkdir()
     # Path must exist to be recognised as a local git remote.
     assert Git._git_remote_to_pip_url(str(path)) == path.as_uri()
diff --git a/tests/unit/test_vcs_mercurial.py b/tests/unit/test_vcs_mercurial.py
index 22ec2b60ed4..fb8eb843d18 100644
--- a/tests/unit/test_vcs_mercurial.py
+++ b/tests/unit/test_vcs_mercurial.py
@@ -3,29 +3,30 @@
 """
 
 import configparser
-import os
+import pathlib
 
 from pip._internal.utils.misc import hide_url
 from pip._internal.vcs.mercurial import Mercurial
 from tests.lib import need_mercurial
-from tests.lib.path import Path
 
 
 @need_mercurial
-def test_mercurial_switch_updates_config_file_when_found(tmpdir: Path) -> None:
+def test_mercurial_switch_updates_config_file_when_found(
+    tmp_path: pathlib.Path,
+) -> None:
     hg = Mercurial()
     options = hg.make_rev_options()
-    hg_dir = os.path.join(tmpdir, ".hg")
-    os.mkdir(hg_dir)
+    hg_dir = tmp_path.joinpath(".hg")
+    hg_dir.mkdir()
 
     config = configparser.RawConfigParser()
     config.add_section("paths")
     config.set("paths", "default", "old_url")
 
-    hgrc_path = os.path.join(hg_dir, "hgrc")
-    with open(hgrc_path, "w") as f:
+    hgrc_path = hg_dir.joinpath("hgrc")
+    with hgrc_path.open("w") as f:
         config.write(f)
-    hg.switch(tmpdir, hide_url("new_url"), options)
+    hg.switch(str(tmp_path), hide_url("new_url"), options)
 
     config.read(hgrc_path)
 
diff --git a/tests/unit/test_wheel.py b/tests/unit/test_wheel.py
index a698656b2df..75d8ef9b696 100644
--- a/tests/unit/test_wheel.py
+++ b/tests/unit/test_wheel.py
@@ -26,7 +26,6 @@
 from pip._internal.utils.misc import hash_file
 from pip._internal.utils.unpacking import unpack_file
 from tests.lib import DATA_DIR, TestData, assert_paths_equal
-from tests.lib.path import Path
 from tests.lib.wheel import make_wheel
 
 
@@ -172,8 +171,11 @@ def test_normalized_outrows(
     assert actual == expected
 
 
-def call_get_csv_rows_for_installed(tmpdir: Path, text: str) -> List[InstalledCSVRow]:
-    path = tmpdir.joinpath("temp.txt")
+def call_get_csv_rows_for_installed(
+    tmp_path: pathlib.Path,
+    text: str,
+) -> List[InstalledCSVRow]:
+    path = tmp_path.joinpath("temp.txt")
     path.write_text(text)
 
     # Test that an installed file appearing in RECORD has its filename
@@ -194,7 +196,7 @@ def call_get_csv_rows_for_installed(tmpdir: Path, text: str) -> List[InstalledCS
 
 
 def test_get_csv_rows_for_installed(
-    tmpdir: Path, caplog: pytest.LogCaptureFixture
+    tmp_path: pathlib.Path, caplog: pytest.LogCaptureFixture
 ) -> None:
     text = textwrap.dedent(
         """\
@@ -202,7 +204,7 @@ def test_get_csv_rows_for_installed(
     d,e,f
     """
     )
-    outrows = call_get_csv_rows_for_installed(tmpdir, text)
+    outrows = call_get_csv_rows_for_installed(tmp_path, text)
 
     expected = [
         ("z", "b", "c"),
@@ -214,7 +216,7 @@ def test_get_csv_rows_for_installed(
 
 
 def test_get_csv_rows_for_installed__long_lines(
-    tmpdir: Path, caplog: pytest.LogCaptureFixture
+    tmp_path: pathlib.Path, caplog: pytest.LogCaptureFixture
 ) -> None:
     text = textwrap.dedent(
         """\
@@ -223,7 +225,7 @@ def test_get_csv_rows_for_installed__long_lines(
     h,i,j,k
     """
     )
-    outrows = call_get_csv_rows_for_installed(tmpdir, text)
+    outrows = call_get_csv_rows_for_installed(tmp_path, text)
     assert outrows == [
         ("z", "b", "c"),
         ("e", "f", "g"),
@@ -258,14 +260,14 @@ def test_dist_from_broken_wheel_fails(data: TestData) -> None:
 
     package = data.packages.joinpath("corruptwheel-1.0-py2.py3-none-any.whl")
     with pytest.raises(InvalidWheel):
-        get_wheel_distribution(FilesystemWheel(package), "brokenwheel")
+        get_wheel_distribution(FilesystemWheel(str(package)), "brokenwheel")
 
 
 class TestWheelFile:
-    def test_unpack_wheel_no_flatten(self, tmpdir: Path) -> None:
+    def test_unpack_wheel_no_flatten(self, tmp_path: pathlib.Path) -> None:
         filepath = os.path.join(DATA_DIR, "packages", "meta-1.0-py2.py3-none-any.whl")
-        unpack_file(filepath, tmpdir)
-        assert os.path.isdir(os.path.join(tmpdir, "meta-1.0.dist-info"))
+        unpack_file(filepath, str(tmp_path))
+        assert tmp_path.joinpath("meta-1.0.dist-info").is_dir()
 
 
 class TestInstallUnpackedWheel:
@@ -273,12 +275,12 @@ class TestInstallUnpackedWheel:
     Tests for moving files from wheel src to scheme paths
     """
 
-    def prep(self, data: TestData, tmpdir: str) -> None:
+    def prep(self, tmp_path: pathlib.Path) -> None:
         # Since Path implements __add__, os.path.join returns a Path object.
         # Passing Path objects to interfaces expecting str (like
         # `compileall.compile_file`) can cause failures, so we normalize it
         # to a string here.
-        tmpdir = str(tmpdir)
+        tmpdir = str(tmp_path)
         self.name = "sample"
         self.wheelpath = make_wheel(
             "sample",
@@ -360,8 +362,9 @@ def assert_installed(self, expected_permission: int) -> None:
         pkg_data = os.path.join(self.scheme.purelib, "sample", "package_data.dat")
         assert os.path.isfile(pkg_data)
 
-    def test_std_install(self, data: TestData, tmpdir: Path) -> None:
-        self.prep(data, tmpdir)
+    @pytest.mark.usefixtures("data")
+    def test_std_install(self, tmp_path: pathlib.Path) -> None:
+        self.prep(tmp_path)
         wheel.install_wheel(
             self.name,
             self.wheelpath,
@@ -370,16 +373,17 @@ def test_std_install(self, data: TestData, tmpdir: Path) -> None:
         )
         self.assert_installed(0o644)
 
+    @pytest.mark.usefixtures("data")
     @pytest.mark.parametrize("user_mask, expected_permission", [(0o27, 0o640)])
     def test_std_install_with_custom_umask(
-        self, data: TestData, tmpdir: Path, user_mask: int, expected_permission: int
+        self, tmp_path: pathlib.Path, user_mask: int, expected_permission: int
     ) -> None:
         """Test that the files created after install honor the permissions
         set when the user sets a custom umask"""
 
         prev_umask = os.umask(user_mask)
         try:
-            self.prep(data, tmpdir)
+            self.prep(tmp_path)
             wheel.install_wheel(
                 self.name,
                 self.wheelpath,
@@ -390,8 +394,9 @@ def test_std_install_with_custom_umask(
         finally:
             os.umask(prev_umask)
 
-    def test_std_install_requested(self, data: TestData, tmpdir: Path) -> None:
-        self.prep(data, tmpdir)
+    @pytest.mark.usefixtures("data")
+    def test_std_install_requested(self, tmp_path: pathlib.Path) -> None:
+        self.prep(tmp_path)
         wheel.install_wheel(
             self.name,
             self.wheelpath,
@@ -403,14 +408,15 @@ def test_std_install_requested(self, data: TestData, tmpdir: Path) -> None:
         requested_path = os.path.join(self.dest_dist_info, "REQUESTED")
         assert os.path.isfile(requested_path)
 
-    def test_std_install_with_direct_url(self, data: TestData, tmpdir: Path) -> None:
+    @pytest.mark.usefixtures("data")
+    def test_std_install_with_direct_url(self, tmp_path: pathlib.Path) -> None:
         """Test that install_wheel creates direct_url.json metadata when
         provided with a direct_url argument. Also test that the RECORDS
         file contains an entry for direct_url.json in that case.
         Note direct_url.url is intentionally different from wheelpath,
         because wheelpath is typically the result of a local build.
         """
-        self.prep(data, tmpdir)
+        self.prep(tmp_path)
         direct_url = DirectUrl(
             url="file:///home/user/archive.tgz",
             info=ArchiveInfo(),
@@ -432,14 +438,15 @@ def test_std_install_with_direct_url(self, data: TestData, tmpdir: Path) -> None
         with open(os.path.join(self.dest_dist_info, "RECORD")) as f2:
             assert DIRECT_URL_METADATA_NAME in f2.read()
 
-    def test_install_prefix(self, data: TestData, tmpdir: Path) -> None:
+    @pytest.mark.usefixtures("data")
+    def test_install_prefix(self, tmp_path: pathlib.Path) -> None:
         prefix = os.path.join(os.path.sep, "some", "path")
-        self.prep(data, tmpdir)
+        self.prep(tmp_path)
         scheme = get_scheme(
             self.name,
             user=False,
             home=None,
-            root=str(tmpdir),  # Casting needed for CPython 3.10+. See GH-10358.
+            root=str(tmp_path),
             isolated=False,
             prefix=prefix,
         )
@@ -451,15 +458,16 @@ def test_install_prefix(self, data: TestData, tmpdir: Path) -> None:
         )
 
         bin_dir = "Scripts" if WINDOWS else "bin"
-        assert os.path.exists(os.path.join(tmpdir, "some", "path", bin_dir))
-        assert os.path.exists(os.path.join(tmpdir, "some", "path", "my_data"))
+        assert os.path.exists(os.path.join(tmp_path, "some", "path", bin_dir))
+        assert os.path.exists(os.path.join(tmp_path, "some", "path", "my_data"))
 
-    def test_dist_info_contains_empty_dir(self, data: TestData, tmpdir: Path) -> None:
+    @pytest.mark.usefixtures("data")
+    def test_dist_info_contains_empty_dir(self, tmp_path: pathlib.Path) -> None:
         """
         Test that empty dirs are not installed
         """
         # e.g. https://github.com/pypa/pip/issues/1632#issuecomment-38027275
-        self.prep(data, tmpdir)
+        self.prep(tmp_path)
         wheel.install_wheel(
             self.name,
             self.wheelpath,
@@ -469,14 +477,15 @@ def test_dist_info_contains_empty_dir(self, data: TestData, tmpdir: Path) -> Non
         self.assert_installed(0o644)
         assert not os.path.isdir(os.path.join(self.dest_dist_info, "empty_dir"))
 
+    @pytest.mark.usefixtures("data")
     @pytest.mark.parametrize("path", ["/tmp/example", "../example", "./../example"])
     def test_wheel_install_rejects_bad_paths(
-        self, data: TestData, tmpdir: Path, path: str
+        self, tmp_path: pathlib.Path, path: str
     ) -> None:
-        self.prep(data, tmpdir)
+        self.prep(tmp_path)
         wheel_path = make_wheel(
             "simple", "0.1.0", extra_files={path: "example contents\n"}
-        ).save_to_dir(tmpdir)
+        ).save_to_dir(tmp_path)
         with pytest.raises(InstallationError) as e:
             wheel.install_wheel(
                 "simple",
@@ -490,15 +499,16 @@ def test_wheel_install_rejects_bad_paths(
         assert "example" in exc_text
 
     @pytest.mark.xfail(strict=True)
+    @pytest.mark.usefixtures("data")
     @pytest.mark.parametrize("entrypoint", ["hello = hello", "hello = hello:"])
     @pytest.mark.parametrize("entrypoint_type", ["console_scripts", "gui_scripts"])
     def test_invalid_entrypoints_fail(
-        self, data: TestData, tmpdir: Path, entrypoint: str, entrypoint_type: str
+        self, tmp_path: pathlib.Path, entrypoint: str, entrypoint_type: str
     ) -> None:
-        self.prep(data, tmpdir)
+        self.prep(tmp_path)
         wheel_path = make_wheel(
             "simple", "0.1.0", entry_points={entrypoint_type: [entrypoint]}
-        ).save_to_dir(tmpdir)
+        ).save_to_dir(tmp_path)
         with pytest.raises(InstallationError) as e:
             wheel.install_wheel(
                 "simple",
@@ -657,11 +667,11 @@ def test_multi_script_all_tilde_not_at_start__multi_dir_not_on_PATH(self) -> Non
 
 
 class TestWheelHashCalculators:
-    def prep(self, tmpdir: Path) -> None:
-        self.test_file = tmpdir.joinpath("hash.file")
+    def prep(self, tmp_path: pathlib.Path) -> None:
+        self.test_file = tmp_path.joinpath("hash.file")
         # Want this big enough to trigger the internal read loops.
         self.test_file_len = 2 * 1024 * 1024
-        with open(str(self.test_file), "w") as fp:
+        with self.test_file.open("w") as fp:
             fp.truncate(self.test_file_len)
         self.test_file_hash = (
             "5647f05ec18958947d32874eeb788fa396a05d0bab7c1b71f112ceb7e9b31eee"
@@ -670,14 +680,14 @@ def prep(self, tmpdir: Path) -> None:
             "sha256=VkfwXsGJWJR9ModO63iPo5agXQurfBtx8RLOt-mzHu4"
         )
 
-    def test_hash_file(self, tmpdir: Path) -> None:
-        self.prep(tmpdir)
-        h, length = hash_file(self.test_file)
+    def test_hash_file(self, tmp_path: pathlib.Path) -> None:
+        self.prep(tmp_path)
+        h, length = hash_file(str(self.test_file))
         assert length == self.test_file_len
         assert h.hexdigest() == self.test_file_hash
 
-    def test_rehash(self, tmpdir: Path) -> None:
-        self.prep(tmpdir)
-        h, length = wheel.rehash(self.test_file)
+    def test_rehash(self, tmp_path: pathlib.Path) -> None:
+        self.prep(tmp_path)
+        h, length = wheel.rehash(str(self.test_file))
         assert length == str(self.test_file_len)
         assert h == self.test_file_hash_encoded
diff --git a/tests/unit/test_wheel_builder.py b/tests/unit/test_wheel_builder.py
index 0468273d66a..74d115a9f3a 100644
--- a/tests/unit/test_wheel_builder.py
+++ b/tests/unit/test_wheel_builder.py
@@ -178,12 +178,12 @@ def test_should_cache_git_sha(script: PipTestEnvironment) -> None:
 
     # a link referencing a sha should be cached
     url = "git+https://g.c/o/r@" + commit + "#egg=mypkg"
-    req = ReqMock(link=Link(url), source_dir=repo_path)
+    req = ReqMock(link=Link(url), source_dir=str(repo_path))
     assert wheel_builder._should_cache(cast(InstallRequirement, req))
 
     # a link not referencing a sha should not be cached
     url = "git+https://g.c/o/r@master#egg=mypkg"
-    req = ReqMock(link=Link(url), source_dir=repo_path)
+    req = ReqMock(link=Link(url), source_dir=str(repo_path))
     assert not wheel_builder._should_cache(cast(InstallRequirement, req))
 
 
diff --git a/tools/protected_pip.py b/tools/protected_pip.py
index 671518029a5..48230719ee2 100644
--- a/tools/protected_pip.py
+++ b/tools/protected_pip.py
@@ -1,15 +1,16 @@
 import os
+import pathlib
 import shutil
 import subprocess
 import sys
 from glob import glob
-from typing import List
+from typing import Iterable, Union
 
 VIRTUAL_ENV = os.environ["VIRTUAL_ENV"]
 TOX_PIP_DIR = os.path.join(VIRTUAL_ENV, "pip")
 
 
-def pip(args: List[str]) -> None:
+def pip(args: Iterable[Union[str, pathlib.Path]]) -> None:
     # First things first, get a recent (stable) version of pip.
     if not os.path.exists(TOX_PIP_DIR):
         subprocess.check_call(
@@ -30,7 +31,7 @@ def pip(args: List[str]) -> None:
     pypath = pypath_env.split(os.pathsep) if pypath_env is not None else []
     pypath.insert(0, TOX_PIP_DIR)
     os.environ["PYTHONPATH"] = os.pathsep.join(pypath)
-    subprocess.check_call([sys.executable, "-m", "pip"] + args)
+    subprocess.check_call([sys.executable, "-m", "pip", *(os.fspath(a) for a in args)])
 
 
 if __name__ == "__main__":