我有一个接受默认参数的方法:
I have a method that accepts default arguments:
def build_url(endpoint, host=settings.DEFAULT_HOST): return '{}{}'.format(host, endpoint)我有一个使用此方法的测试用例:
I have a test case that exercises this method:
class BuildUrlTestCase(TestCase): def test_build_url(self): """ If host and endpoint are supplied result should be 'host/endpoint' """ result = build_url('/end', 'host') expected = 'host/end' self.assertEqual(result,expected) @patch('myapp.settings') def test_build_url_with_default(self, mock_settings): """ If only endpoint is supplied should default to settings""" mock_settings.DEFAULT_HOST = 'domain' result = build_url('/end') expected = 'domain/end' self.assertEqual(result,expected)如果我将调试点放在build_url中并检查此属性,则settings.DEFAULT_HOST返回模拟值.但是,测试继续失败,并且断言指示host被分配了我实际的settings.py中的值.我知道这是因为host关键字参数是在导入时设置的,并且未考虑我的模拟.
If I drop a debug point in build_url and inspect this attribute settings.DEFAULT_HOST returns the mocked value. However the test continues to fail and the assertion indicates host is assigned the value from my actual settings.py. I know this is because the host keyword argument is set at import time and my mock is not considered.
调试器
(Pdb) settings <MagicMock name='settings' id='85761744'> (Pdb) settings.DEFAULT_HOST 'domain' (Pdb) host 'host-from-settings'是否可以在测试时覆盖此值,以便可以使用模拟的settings对象行使默认路径?
Is there a way to override this value at test time so that I can exercise the default path with a mocked settings object?
推荐答案定义函数后,函数会将其参数默认值存储在func_defaults属性中,因此您可以对其进行修补.像
Functions store their parameter default values in the func_defaults attribute when the function is defined, so you can patch that. Something like
def test_build_url(self): """ If only endpoint is supplied should default to settings""" # Use `func_defaults` in Python2.x and `__defaults__` in Python3.x. with patch.object(build_url, 'func_defaults', ('domain',)): result = build_url('/end') expected = 'domain/end' self.assertEqual(result,expected)我使用patch.object作为上下文管理器而不是装饰器,以避免不必要的补丁对象作为参数传递给test_build_url.
I use patch.object as a context manager rather than a decorator to avoid the unnecessary patch object being passed as an argument to test_build_url.
更多推荐
Python unittest模拟:是否可以在测试时模拟方法的默认参数的值?
发布评论