TST: Mark test_submodule.TestSubmodule.test_root_module as xfail on Cygwin

Author: DWesl

test/test_submodule.py

@@ -3,8 +3,11 @@
 # the BSD License: http://www.opensource.org/licenses/bsd-license.php
 import os
 import shutil
+import sys
 from unittest import skipIf
 
+import pytest
+
 import git
 from git.cmd import Git
 from git.compat import is_win
@@ -433,6 +436,11 @@ def _do_base_tests(self, rwrepo):
     def test_base_rw(self, rwrepo):
         self._do_base_tests(rwrepo)
 
+    @pytest.mark.xfail(
+        sys.platform == "cygwin",
+        reason="Cygwin GitPython can't find submodule SHA",
+        raises=ValueError
+    )
     @with_rw_repo(k_subm_current, bare=True)
     def test_base_bare(self, rwrepo):
         self._do_base_tests(rwrepo)