old_contents: import functools
  import importlib._bootstrap
  
  
  using___import__ = False
  
  
  def import_(*args, **kwargs):
      """Delegate to allow for injecting different implementations of import."""
      if using___import__:
          return __import__(*args, **kwargs)
      else:
          return importlib._bootstrap.__import__(*args, **kwargs)
  
  
  def importlib_only(fxn):
      """Decorator to mark which tests are not supported by the current
      implementation of __import__()."""
      def inner(*args, **kwargs):
          if using___import__:
              return
          else:
              return fxn(*args, **kwargs)
      functools.update_wrapper(inner, fxn)
      return inner
  
  
  def mock_path_hook(*entries, importer):
      """A mock sys.path_hooks entry."""
      def hook(entry):
          if entry not in entries:
              raise ImportError
          return importer
      return hook
  
new_contents: import functools
  import importlib
  import importlib._bootstrap
  import unittest
  
  
  using___import__ = False
  
  
  def import_(*args, **kwargs):
      """Delegate to allow for injecting different implementations of import."""
      if using___import__:
          return __import__(*args, **kwargs)
      else:
          return importlib._bootstrap.__import__(*args, **kwargs)
  
  
  importlib_only = unittest.skipIf(using___import__, "importlib-specific test")
  
  
  def mock_path_hook(*entries, importer):
      """A mock sys.path_hooks entry."""
      def hook(entry):
          if entry not in entries:
              raise ImportError
          return importer
      return hook
  
subject: Move a test-skipping decorator over to unittest.skipIf.