模拟 python 库或包装方法

Question

在我的代码release_bundler.py文件中class MavenDependenciesPathsBuilderStrategy(PathsBuilderStrategy):  def build_bundler_copy_paths(self, mapping_values):    source = join(getcwd(),'target','dependency',mapping_values[0])    destination = join(getcwd(),'target','generated-resources',mapping_values[1],mapping_values[0])    return [source, destination]class NestedModulePathsFilterStrategy(FilterStrategy):  def filter_changeset_paths(self, changeset_paths, bundling_map, paths_builder_strategy):    for mapping_key in bundling_map.keys():      if(mapping_key in changeset_paths):        mapping_values = bundling_map.get(mapping_key).values()        copy_paths = paths_builder_strategy.build_bundler_copy_paths(mapping_values)        return copy_paths如果我想测试该filter_changeset_paths方法，我必须在getcwd方法内模拟这两种方法，build_bundler_copy_paths还是只模拟后者呢？我尝试在我的测试中模拟该方法release_bundler_test.py，导入如下分类：from release_bundler import NestedModulePathsFilterStrategy, MavenDependenciesPathsBuilderStrategy然后修补MavenDependenciesPathsBuilderStrategy课程def mock_build_bundler_copy_paths(self, mapping_values):  return ['/cwd/foo','/cwd/bar']但我不认为这个模拟有效，因为self.assertIsNotNone(result)失败所以问题是：我嘲笑的方式正确吗？无法理解会嘲笑该MavenDependenciesPathsBuilderStrategy方法还是我也必须嘲笑os.getcwd它的内部方法？