mock.py 文件源码

def environ(env_name, env_value):
    """Mock environment variable value.

    Example::

        @mock.environ('DJANGO_SETTINGS_MODULE', 'proj.settings')
        def test_other_settings(self):
            ...

    """
    sentinel = object()
    prev_val = os.environ.get(env_name, sentinel)
    os.environ[env_name] = env_value
    try:
        yield
    finally:
        if prev_val is sentinel:
            os.environ.pop(env_name, None)
        else:
            os.environ[env_name] = prev_val