mock.py 文件源码

def __init__(self, module_name):
        if Mock.active:
            print("Previous mock object still alive")
        Mock.active = True

        self.module = sys.modules[module_name]

        self.mocks = {}
        self.calls = defaultdict(list)
        self.opened = {}
        self.filesystem = {}

        # default mocks
        self.stderr = sys.stderr
        sys.stderr = sys.stdout

        self = weakref.proxy(self)
        self.mock(self.module, 'open', lambda *args, **kwargs: self.open(*args, **kwargs))
        if hasattr(self.module, 'os'):
            self.mock(self.module.os.path, 'exists', lambda *args, **kwargs: self.exists(*args, **kwargs))
            self.mock(self.module.os, 'walk', lambda *args, **kwargs: self.walk(*args, **kwargs))