Call os.path.normpath to normalize paths for comp

changelog.d/1519.change.rst

@@ -0,0 +1 @@
+In ``pkg_resources.normalize_path``, additional path normalization is now performed to ensure path values to a directory is always the same, preventing false positives when checking scripts have a consistent prefix to set up on Windows.

pkg_resources/__init__.py

@@ -2228,7 +2228,7 @@ def null_ns_handler(importer, path_item, packageName, module):
 
 def normalize_path(filename):
     """Normalize a file/dir name for comparison purposes"""
-    return os.path.normcase(os.path.realpath(_cygwin_patch(filename)))
+    return os.path.normcase(os.path.realpath(os.path.normpath(_cygwin_patch(filename))))
 
 
 def _cygwin_patch(filename):  # pragma: nocover

pkg_resources/tests/test_pkg_resources.py

@@ -236,3 +236,56 @@ def test_version_resolved_from_egg_info(self, env):
         req = pkg_resources.Requirement.parse('foo>=1.9')
         dist = pkg_resources.WorkingSet([env.paths['lib']]).find(req)
         assert dist.version == version
+
+    @pytest.mark.parametrize(
+        'unnormalized, normalized',
+        [
+            ('foo', 'foo'),
+            ('foo/', 'foo'),
+            ('foo/bar', 'foo/bar'),
+            ('foo/bar/', 'foo/bar'),
+        ],
+    )
+    def test_normalize_path_trailing_sep(self, unnormalized, normalized):
+        """Ensure the trailing slash is cleaned for path comparison.
+
+        See pypa/setuptools#1519.
+        """
+        result_from_unnormalized = pkg_resources.normalize_path(unnormalized)
+        result_from_normalized = pkg_resources.normalize_path(normalized)
+        assert result_from_unnormalized == result_from_normalized
+
+    @pytest.mark.skipif(
+        os.path.normcase('A') != os.path.normcase('a'),
+        reason='Testing case-insensitive filesystems.',
+    )
+    @pytest.mark.parametrize(
+        'unnormalized, normalized',
+        [
+            ('MiXeD/CasE', 'mixed/case'),
+        ],
+    )
+    def test_normalize_path_normcase(self, unnormalized, normalized):
+        """Ensure mixed case is normalized on case-insensitive filesystems.
+        """
+        result_from_unnormalized = pkg_resources.normalize_path(unnormalized)
+        result_from_normalized = pkg_resources.normalize_path(normalized)
+        assert result_from_unnormalized == result_from_normalized
+
+    @pytest.mark.skipif(
+        os.path.sep != '\\',
+        reason='Testing systems using backslashes as path separators.',
+    )
+    @pytest.mark.parametrize(
+        'unnormalized, expected',
+        [
+            ('forward/slash', 'forward\\slash'),
+            ('forward/slash/', 'forward\\slash'),
+            ('backward\\slash\\', 'backward\\slash'),
+        ],
+    )
+    def test_normalize_path_backslash_sep(self, unnormalized, expected):
+        """Ensure path seps are cleaned on backslash path sep systems.
+        """
+        result = pkg_resources.normalize_path(unnormalized)
+        assert result.endswith(expected)