diff --git a/tests/test-convert-git.t b/tests/test-convert-git.t
--- a/tests/test-convert-git.t
+++ b/tests/test-convert-git.t
@@ -283,9 +283,12 @@ damage git repository and convert again
 
   $ cat > damage.py <<EOF
   > import os
+  > import stat
   > for root, dirs, files in os.walk('git-repo4/.git/objects'):
   >     if files:
   >         path = os.path.join(root, files[0])
+  >         if os.name == 'nt':
+  >             os.chmod(path, stat.S_IWUSR)
   >         os.remove(path)
   >         break
   > EOF