better no-cover for windows

pre_commit/file_lock.py

@@ -41,14 +41,14 @@ try:  # pragma: no cover (windows)
             # "Regions should be locked only briefly and should be unlocked
             # before closing a file or exiting the program."
             msvcrt.locking(fileno, msvcrt.LK_UNLCK, _region)
-except ImportError:  # pragma: no cover (posix)
+except ImportError:  # pragma: windows no cover
     import fcntl
 
     @contextlib.contextmanager
     def _locked(fileno, blocked_cb):
         try:
             fcntl.flock(fileno, fcntl.LOCK_EX | fcntl.LOCK_NB)
-        except IOError:
+        except IOError:  # pragma: no cover (tests are single-threaded)
             blocked_cb()
             fcntl.flock(fileno, fcntl.LOCK_EX)
         try:

pre_commit/languages/node.py

@@ -28,7 +28,7 @@ def get_env_patch(venv):
         install_prefix = r'{}\bin'.format(win_venv.strip())
     elif sys.platform == 'win32':  # pragma: no cover
         install_prefix = bin_dir(venv)
-    else:
+    else:  # pragma: windows no cover
         install_prefix = venv
     return (
         ('NODE_VIRTUAL_ENV', venv),