diff --git a/.github/workflows/build.yaml b/.github/workflows/build.yaml
index 3c3f7fa..1df4b19 100644
--- a/.github/workflows/build.yaml
+++ b/.github/workflows/build.yaml
@@ -91,6 +91,9 @@ jobs:
     - name: Run Tests
       run: |
         bazel test //...
+    - name: Run Tests (WORKSPACE.bazel)
+      run: |
+        bazel test //... --noenable_bzlmod
     - name: Perform compilation
       run: |
         bazel run //3rdparty:requirements_compiler "--" --upgrade
diff --git a/.gitignore b/.gitignore
index 27c1a3b..2efc21d 100644
--- a/.gitignore
+++ b/.gitignore
@@ -12,3 +12,4 @@ dist
 /bazel-*
 user.bazelrc
 /.github/ci.bazelrc
+/private/examples/multiplatform_py_test/bazel-*
diff --git a/WORKSPACE.bazel b/WORKSPACE.bazel
index 743ad21..c7019a4 100644
--- a/WORKSPACE.bazel
+++ b/WORKSPACE.bazel
@@ -1 +1,32 @@
-# Use MODULE.bazel instead.
+workspace(name = "rules_req_compile")
+
+load("//:repositories.bzl", "req_compile_dependencies")
+
+req_compile_dependencies()
+
+load("//:repositories_transitive.bzl", "req_compile_transitive_dependencies")
+
+req_compile_transitive_dependencies()
+
+load("@rules_python//python:repositories.bzl", "python_register_toolchains")
+
+python_register_toolchains(
+    name = "python311",
+    python_version = "3.11",
+)
+
+load("@bazel_skylib//:workspace.bzl", "bazel_skylib_workspace")
+
+bazel_skylib_workspace()
+
+load("//private/tests:test_repositories_1.bzl", "test_dependencies_1")
+
+test_dependencies_1()
+
+load("//private/tests:test_repositories_2.bzl", "test_dependencies_2")
+
+test_dependencies_2()
+
+load("//private/tests:test_repositories_3.bzl", "test_dependencies_3")
+
+test_dependencies_3()
diff --git a/private/tests/annotations/annotations_test_deps.bzl b/private/tests/annotations/annotations_test_deps.bzl
new file mode 100644
index 0000000..ba08126
--- /dev/null
+++ b/private/tests/annotations/annotations_test_deps.bzl
@@ -0,0 +1,78 @@
+"""Test dependencies for the annotations integration test"""
+
+load("@bazel_tools//tools/build_defs/repo:utils.bzl", "maybe")
+load(
+    "//:defs.bzl",
+    "py_requirements_repository",
+    package_annotation = "py_package_annotation",
+)
+
+_NUMPY_LIBRARY_TARGET = """\
+load("@rules_cc//cc:defs.bzl", "cc_library")
+load("@rules_req_compile//:defs.bzl", "py_package_annotation_target")
+
+_INCLUDE_DIR = "site-packages/numpy/core/include"
+
+cc_library(
+    name = "headers",
+    hdrs = glob(["{}/**/*.h".format(_INCLUDE_DIR)]),
+    includes = [_INCLUDE_DIR],
+)
+
+py_package_annotation_target(
+    name = "pkg.headers",
+    target = ":headers",
+)
+"""
+
+def req_compile_test_annotations_deps():
+    maybe(
+        py_requirements_repository,
+        name = "req_compile_test_annotations",
+        requirements_locks = {
+            Label("//private/tests/annotations:requirements.linux.txt"): "@platforms//os:linux",
+            Label("//private/tests/annotations:requirements.macos.txt"): "@platforms//os:macos",
+            Label("//private/tests/annotations:requirements.windows.txt"): "@platforms//os:windows",
+        },
+        annotations = {
+            "numpy": package_annotation(
+                additive_build_file_content = _NUMPY_LIBRARY_TARGET,
+                data = [":pkg.headers"],
+                copy_srcs = {
+                    "site-packages/numpy/conftest.py": "site-packages/numpy/conftest.copy.py",
+                },
+                copy_files = {
+                    "site-packages/numpy-1.26.4.dist-info/entry_points.txt": "site-packages/numpy-1.26.4.dist-info/entry_points.copy.txt",
+                },
+                copy_executables = {
+                    "site-packages/numpy/testing/setup.py": "site-packages/numpy/testing/setup.copy.py",
+                },
+                patches = [
+                    Label("//private/tests/annotations:numpy.patch"),
+                ],
+                deps = [
+                    # Show that label dependencies can be added.
+                    Label("@rules_python//python/runfiles"),
+                ],
+            ),
+            # Sphinx is known to have a circular dependency. The annotations here solve for that.
+            "sphinxcontrib-applehelp": package_annotation(
+                deps = ["-sphinx"],
+            ),
+            "sphinxcontrib-devhelp": package_annotation(
+                deps = ["-sphinx"],
+            ),
+            "sphinxcontrib-htmlhelp": package_annotation(
+                deps = ["-sphinx"],
+            ),
+            "sphinxcontrib-jsmath": package_annotation(
+                deps_excludes = ["sphinx"],
+            ),
+            "sphinxcontrib-qthelp": package_annotation(
+                deps_excludes = ["sphinx"],
+            ),
+            "sphinxcontrib-serializinghtml": package_annotation(
+                deps_excludes = ["sphinx"],
+            ),
+        },
+    )
diff --git a/private/tests/pip_parse_compat/pip_parse_compat_test_deps.bzl b/private/tests/pip_parse_compat/pip_parse_compat_test_deps.bzl
new file mode 100644
index 0000000..8b7e5e8
--- /dev/null
+++ b/private/tests/pip_parse_compat/pip_parse_compat_test_deps.bzl
@@ -0,0 +1,21 @@
+"""Test dependencies for `pip_parse` compatibility tests"""
+
+load("@bazel_tools//tools/build_defs/repo:utils.bzl", "maybe")
+load("//:defs.bzl", "py_requirements_repository")
+
+def pip_parse_compat_test_deps():
+    maybe(
+        py_requirements_repository,
+        name = "req_compile_test_pip_parse_compat_single_plat",
+        requirements_lock = Label("//private/tests/pip_parse_compat:requirements.txt"),
+    )
+
+    maybe(
+        py_requirements_repository,
+        name = "req_compile_test_pip_parse_compat_multi_plat",
+        requirements_locks = {
+            Label("//private/tests/pip_parse_compat:requirements.linux.txt"): "@platforms//os:linux",
+            Label("//private/tests/pip_parse_compat:requirements.macos.txt"): "@platforms//os:macos",
+            Label("//private/tests/pip_parse_compat:requirements.windows.txt"): "@platforms//os:windows",
+        },
+    )
diff --git a/private/tests/pip_parse_compat/pip_parse_compat_test_deps_install.bzl b/private/tests/pip_parse_compat/pip_parse_compat_test_deps_install.bzl
new file mode 100644
index 0000000..36b0082
--- /dev/null
+++ b/private/tests/pip_parse_compat/pip_parse_compat_test_deps_install.bzl
@@ -0,0 +1,14 @@
+"""Test dependencies for `pip_parse` compatibility tests"""
+
+load(
+    "@req_compile_test_pip_parse_compat_multi_plat//:requirements.bzl",
+    pip_parse_compat_multi_plat_repositories = "install_deps",
+)
+load(
+    "@req_compile_test_pip_parse_compat_single_plat//:requirements.bzl",
+    pip_parse_compat_single_plat_repositories = "install_deps",
+)
+
+def pip_parse_compat_test_deps_install():
+    pip_parse_compat_multi_plat_repositories()
+    pip_parse_compat_single_plat_repositories()
diff --git a/private/tests/test_repositories_1.bzl b/private/tests/test_repositories_1.bzl
new file mode 100644
index 0000000..c7223ec
--- /dev/null
+++ b/private/tests/test_repositories_1.bzl
@@ -0,0 +1,56 @@
+"""req-compile Bazel integration test dependencies"""
+
+load("@bazel_tools//tools/build_defs/repo:utils.bzl", "maybe")
+load("@python311//:defs.bzl", "interpreter")
+load("//:defs.bzl", "py_requirements_repository")
+load("//private/tests/annotations:annotations_test_deps.bzl", "req_compile_test_annotations_deps")
+load("//private/tests/find_links:find_links_test_repo.bzl", "find_links_test_repository")
+load("//private/tests/pip_parse_compat:pip_parse_compat_test_deps.bzl", "pip_parse_compat_test_deps")
+
+def test_dependencies_1():
+    """req-compile Bazel integration test dependencies"""
+
+    maybe(
+        py_requirements_repository,
+        name = "req_compile_test_sdist",
+        # Required to compile sdists
+        interpreter = interpreter,
+        requirements_lock = Label("//private/tests/sdist:requirements.txt"),
+    )
+
+    maybe(
+        py_requirements_repository,
+        name = "req_compile_test_simple",
+        requirements_lock = Label("//private/tests/simple:requirements.txt"),
+    )
+
+    maybe(
+        py_requirements_repository,
+        name = "req_compile_test_platlib",
+        requirements_locks = {
+            Label("//private/tests/platlib:requirements.linux.txt"): "@platforms//os:linux",
+            Label("//private/tests/platlib:requirements.macos.txt"): "@platforms//os:macos",
+            Label("//private/tests/platlib:requirements.windows.txt"): "@platforms//os:windows",
+        },
+    )
+
+    maybe(
+        py_requirements_repository,
+        name = "req_compile_test_transitive_ins",
+        requirements_lock = Label("//private/tests/transitive_ins:requirements.txt"),
+    )
+
+    maybe(
+        find_links_test_repository,
+        name = "req_compile_find_links_test",
+        pyspark_wheel_data = Label("@req_compile_test_sdist__pyspark__sdist//:whl.json"),
+        build_file = Label("//private/tests/find_links:BUILD.find_links.bazel"),
+        # Needs to match `--find-links` in `//private/tests/find_links:requirements.in`
+        wheeldir = "wheeldir",
+        requirements_in = Label("//private/tests/find_links:requirements.in"),
+        requirements_txt = Label("//private/tests/find_links:requirements.txt"),
+    )
+
+    pip_parse_compat_test_deps()
+
+    req_compile_test_annotations_deps()
diff --git a/private/tests/test_repositories_2.bzl b/private/tests/test_repositories_2.bzl
new file mode 100644
index 0000000..171b639
--- /dev/null
+++ b/private/tests/test_repositories_2.bzl
@@ -0,0 +1,29 @@
+"""req-compile Bazel integration test transitive dependencies"""
+
+load("@bazel_tools//tools/build_defs/repo:utils.bzl", "maybe")
+load("@req_compile_test_annotations//:defs.bzl", annotations_repositories = "repositories")
+load("@req_compile_test_platlib//:defs.bzl", platlib_repositories = "repositories")
+load("@req_compile_test_sdist//:defs.bzl", sdist_repositories = "repositories")
+load("@req_compile_test_simple//:defs.bzl", simple_repositories = "repositories")
+load("@req_compile_test_transitive_ins//:defs.bzl", transitive_ins_repositories = "repositories")
+load("//:defs.bzl", "py_requirements_repository")
+load(
+    "//private/tests/pip_parse_compat:pip_parse_compat_test_deps_install.bzl",
+    "pip_parse_compat_test_deps_install",
+)
+
+def test_dependencies_2():
+    """req-compile Bazel integration test transitive dependencies"""
+
+    annotations_repositories()
+    pip_parse_compat_test_deps_install()
+    platlib_repositories()
+    sdist_repositories()
+    simple_repositories()
+    transitive_ins_repositories()
+
+    maybe(
+        py_requirements_repository,
+        name = "req_compile_test_find_links",
+        requirements_lock = Label("@req_compile_find_links_test//:requirements.txt"),
+    )
diff --git a/private/tests/test_repositories_3.bzl b/private/tests/test_repositories_3.bzl
new file mode 100644
index 0000000..e486f41
--- /dev/null
+++ b/private/tests/test_repositories_3.bzl
@@ -0,0 +1,7 @@
+"""req-compile Bazel integration test transitive dependencies"""
+
+load("@req_compile_test_find_links//:defs.bzl", find_links_repositories = "repositories")
+
+def test_dependencies_3():
+    """req-compile Bazel integration test transitive dependencies"""
+    find_links_repositories()