Bugfix/fix string newlines

README.rst

@@ -43,7 +43,7 @@ This `pytest`_ plugin was generated with `Cookiecutter`_ along with `@hackebrot`
 Features
 --------
 
-* snapshot testing of strings ands bytes
+* snapshot testing of strings and bytes
 * snapshot testing of collections of strings and bytes
 * the user has complete control over the snapshot file path and content
 

pytest_snapshot/plugin.py

@@ -44,6 +44,22 @@ def _assert_equal(value, expected_value) -> None:
         assert expected_value == value
 
 
+def _file_encode(string: str) -> bytes:
+    """
+    Returns the bytes that would be in a file created using ``path.write_text(string)``.
+    See universal newlines documentation.
+    """
+    return string.replace('\n', os.linesep).encode()
+
+
+def _file_decode(data: bytes) -> str:
+    """
+    Returns the string that would be read from a file using ``path.read_text(string)``.
+    See universal newlines documentation.
+    """
+    return data.decode().replace('\r\n', '\n').replace('\r', '\n')
+
+
 class Snapshot:
     _snapshot_update = None  # type: bool
     _allow_snapshot_deletion = None  # type: bool
@@ -120,7 +136,7 @@ def _get_compare_encode_decode(self, value: Union[str, bytes]):
         * The decoding function should decode bytes from a snapshot file into a object.
         """
         if isinstance(value, str):
-            return _assert_equal, str.encode, bytes.decode
+            return _assert_equal, _file_encode, _file_decode
         elif isinstance(value, bytes):
             return _assert_equal, lambda x: x, lambda x: x
         else:

tests/test_assert_match.py

@@ -1,3 +1,5 @@
+import os
+
 import pytest
 
 from tests.utils import assert_pytest_passes
@@ -6,17 +8,17 @@
 @pytest.fixture
 def basic_case_dir(testdir):
     case_dir = testdir.mkdir('case_dir')
-    case_dir.join('snapshot1.txt').write_text('the valuÉ of snapshot1.txt', 'utf-8')
+    case_dir.join('snapshot1.txt').write_text('the valuÉ of snapshot1.txt\n', 'utf-8')
     return case_dir
 
 
 def test_assert_match_with_external_snapshot_path(testdir, basic_case_dir):
-    testdir.makepyfile("""
+    testdir.makepyfile(r"""
         from pathlib import Path
 
         def test_sth(snapshot):
             snapshot.snapshot_dir = 'case_dir'
-            snapshot.assert_match('the value of snapshot1.txt', Path('not_case_dir/snapshot1.txt').absolute())
+            snapshot.assert_match('the value of snapshot1.txt\n', Path('not_case_dir/snapshot1.txt').absolute())
     """)
     result = testdir.runpytest('-v')
     result.stdout.fnmatch_lines([
@@ -27,28 +29,29 @@ def test_sth(snapshot):
 
 
 def test_assert_match_success_string(testdir, basic_case_dir):
-    testdir.makepyfile("""
+    testdir.makepyfile(r"""
         def test_sth(snapshot):
             snapshot.snapshot_dir = 'case_dir'
-            snapshot.assert_match('the valuÉ of snapshot1.txt', 'snapshot1.txt')
+            snapshot.assert_match('the valuÉ of snapshot1.txt\n', 'snapshot1.txt')
     """)
     assert_pytest_passes(testdir)
 
 
 def test_assert_match_success_bytes(testdir, basic_case_dir):
     testdir.makepyfile(r"""
+        import os
         def test_sth(snapshot):
             snapshot.snapshot_dir = 'case_dir'
-            snapshot.assert_match(b'the valu\xc3\x89 of snapshot1.txt', 'snapshot1.txt')
+            snapshot.assert_match(b'the valu\xc3\x89 of snapshot1.txt' + os.linesep.encode(), 'snapshot1.txt')
     """)
     assert_pytest_passes(testdir)
 
 
 def test_assert_match_failure_string(testdir, basic_case_dir):
-    testdir.makepyfile("""
+    testdir.makepyfile(r"""
         def test_sth(snapshot):
             snapshot.snapshot_dir = 'case_dir'
-            snapshot.assert_match('the INCORRECT value of snapshot1.txt', 'snapshot1.txt')
+            snapshot.assert_match('the INCORRECT value of snapshot1.txt\n', 'snapshot1.txt')
     """)
     result = testdir.runpytest('-v')
     result.stdout.fnmatch_lines([
@@ -65,10 +68,11 @@ def test_sth(snapshot):
 
 
 def test_assert_match_failure_bytes(testdir, basic_case_dir):
-    testdir.makepyfile("""
+    testdir.makepyfile(r"""
+        import os
         def test_sth(snapshot):
             snapshot.snapshot_dir = 'case_dir'
-            snapshot.assert_match(b'the INCORRECT value of snapshot1.txt', 'snapshot1.txt')
+            snapshot.assert_match(b'the INCORRECT value of snapshot1.txt' + os.linesep.encode(), 'snapshot1.txt')
     """)
     result = testdir.runpytest('-v')
     result.stdout.fnmatch_lines([
@@ -78,14 +82,14 @@ def test_sth(snapshot):
         r"E* assert * == *",
         r"E* At index 4 diff: * != *",
         r"E* Full diff:",
-        r"E* - b'the valu\xc3\x89 of snapshot1.txt'",
-        r"E* + b'the INCORRECT value of snapshot1.txt'",
+        r"E* - b'the valu\xc3\x89 of snapshot1.txt{}'".format(repr(os.linesep)[1:-1]),
+        r"E* + b'the INCORRECT value of snapshot1.txt{}'".format(repr(os.linesep)[1:-1]),
     ])
     assert result.ret == 1
 
 
 def test_assert_match_invalid_type(testdir, basic_case_dir):
-    testdir.makepyfile("""
+    testdir.makepyfile(r"""
         def test_sth(snapshot):
             snapshot.snapshot_dir = 'case_dir'
             snapshot.assert_match(123, 'snapshot1.txt')
@@ -99,7 +103,7 @@ def test_sth(snapshot):
 
 
 def test_assert_match_missing_snapshot(testdir, basic_case_dir):
-    testdir.makepyfile("""
+    testdir.makepyfile(r"""
         def test_sth(snapshot):
             snapshot.snapshot_dir = 'case_dir'
             snapshot.assert_match('something', 'snapshot_that_doesnt_exist.txt')
@@ -114,10 +118,10 @@ def test_sth(snapshot):
 
 
 def test_assert_match_update_existing_snapshot_no_change(testdir, basic_case_dir):
-    testdir.makepyfile("""
+    testdir.makepyfile(r"""
         def test_sth(snapshot):
             snapshot.snapshot_dir = 'case_dir'
-            snapshot.assert_match('the valuÉ of snapshot1.txt', 'snapshot1.txt')
+            snapshot.assert_match('the valuÉ of snapshot1.txt\n', 'snapshot1.txt')
     """)
     result = testdir.runpytest('-v', '--snapshot-update')
     result.stdout.fnmatch_lines([
@@ -152,12 +156,12 @@ def test_assert_match_update_existing_snapshot(testdir, basic_case_dir, case_dir
 
     Also tests that `Snapshot` supports absolute/relative str/Path snapshot directories and snapshot paths.
     """
-    testdir.makepyfile("""
+    testdir.makepyfile(r"""
         from pathlib import Path
 
         def test_sth(snapshot):
             snapshot.snapshot_dir = {case_dir_repr}
-            snapshot.assert_match('the NEW value of snapshot1.txt', {snapshot_name_repr})
+            snapshot.assert_match('the NEW value of snapshot1.txt\n', {snapshot_name_repr})
     """.format(case_dir_repr=case_dir_repr, snapshot_name_repr=snapshot_name_repr))
     result = testdir.runpytest('-v', '--snapshot-update')
     result.stdout.fnmatch_lines([
@@ -177,12 +181,12 @@ def test_assert_match_update_existing_snapshot_and_exception_in_test(testdir, ba
     Tests that `Snapshot.assert_match` works when updating an existing snapshot and then the test function fails.
     In this case, both the snapshot update error and the test function error are printed out.
     """
-    testdir.makepyfile("""
+    testdir.makepyfile(r"""
         from pathlib import Path
 
         def test_sth(snapshot):
             snapshot.snapshot_dir = 'case_dir'
-            snapshot.assert_match('the NEW value of snapshot1.txt', 'snapshot1.txt')
+            snapshot.assert_match('the NEW value of snapshot1.txt\n', 'snapshot1.txt')
             assert False
     """)
     result = testdir.runpytest('-v', '--snapshot-update')
@@ -198,7 +202,7 @@ def test_sth(snapshot):
 
 
 def test_assert_match_create_new_snapshot(testdir, basic_case_dir):
-    testdir.makepyfile("""
+    testdir.makepyfile(r"""
         def test_sth(snapshot):
             snapshot.snapshot_dir = 'case_dir'
             snapshot.assert_match('the NEW value of new_snapshot1.txt', 'sub_dir/new_snapshot1.txt')
@@ -217,7 +221,7 @@ def test_sth(snapshot):
 
 
 def test_assert_match_create_new_snapshot_in_default_dir(testdir):
-    testdir.makepyfile("""
+    testdir.makepyfile(r"""
         def test_sth(snapshot):
             snapshot.assert_match('the value of new_snapshot1.txt', 'sub_dir/new_snapshot1.txt')
     """)
@@ -239,7 +243,7 @@ def test_sth(snapshot):
 
 def test_assert_match_existing_snapshot_is_not_file(testdir, basic_case_dir):
     basic_case_dir.mkdir('directory1')
-    testdir.makepyfile("""
+    testdir.makepyfile(r"""
         def test_sth(snapshot):
             snapshot.snapshot_dir = 'case_dir'
             snapshot.assert_match('something', 'directory1')