Add more 'no cover windows' comments

pre_commit/commands/install_uninstall.py

@@ -39,7 +39,7 @@ def _hook_paths(hook_type):
 
 
 def is_our_script(filename):
-    if not os.path.exists(filename):
+    if not os.path.exists(filename):  # pragma: windows no cover (symlink)
         return False
     with io.open(filename) as f:
         contents = f.read()

pre_commit/languages/docker.py

@@ -72,7 +72,7 @@ def install_environment(
         os.mkdir(directory)
 
 
-def docker_cmd():
+def docker_cmd():  # pragma: windows no cover
     return (
         'docker', 'run',
         '--rm',