async def METHOD_NAME():
    transport = AsyncMockTransport()
    with mock.patch.dict(ENVIRON, {var: "..." for var in EnvironmentVariables.CLIENT_SECRET_VARS}, clear=True):
        credential = EnvironmentCredential(transport=transport)
    async with credential:
        assert transport.__aenter__.call_count == 1
        assert transport.__aexit__.call_count == 0
    assert transport.__aenter__.call_count == 1
    assert transport.__aexit__.call_count == 1