diff --git a/git/test/test_diff.py b/git/test/test_diff.py
index d34d84e39..d5f5b721b 100644
--- a/git/test/test_diff.py
+++ b/git/test/test_diff.py
@@ -25,6 +25,7 @@
     NULL_TREE,
 )
 import ddt
+from git.cmd import Git
 
 
 @ddt.ddt
@@ -56,7 +57,7 @@ def test_diff_with_staged_file(self, rw_dir):
         fp = os.path.join(rw_dir, 'hello.txt')
         with open(fp, 'w') as fs:
             fs.write("hello world")
-        r.git.add(fp)
+        r.git.add(Git.polish_url(fp))
         r.git.commit(message="init")
 
         with open(fp, 'w') as fs:
diff --git a/git/test/test_submodule.py b/git/test/test_submodule.py
index 9db4f9c90..da3049440 100644
--- a/git/test/test_submodule.py
+++ b/git/test/test_submodule.py
@@ -705,7 +705,7 @@ def test_git_submodules_and_add_sm_with_new_commit(self, rwdir):
         fp = osp.join(smm.working_tree_dir, 'empty-file')
         with open(fp, 'w'):
             pass
-        smm.git.add(fp)
+        smm.git.add(Git.polish_url(fp))
         smm.git.commit(m="new file added")
 
         # submodules are retrieved from the current commit's tree, therefore we can't really get a new submodule
diff --git a/git/util.py b/git/util.py
index 9668f7b3f..992937fb5 100644
--- a/git/util.py
+++ b/git/util.py
@@ -264,6 +264,7 @@ def _cygexpath(drive, path):
 
 
 def cygpath(path):
+    """Use :meth:`git.cmd.Git.polish_url()` instead, that works on any environment."""
     if not path.startswith(('/cygdrive', '//')):
         for regex, parser, recurse in _cygpath_parsers:
             match = regex.match(path)