正确的mock.patch smtplib.SMTP方法

Question

smtplib.SMTP.sendmail尝试在单元测试中模拟.修补调用。该sendmail方法似乎已成功模拟，我们可以将其查询为MagicMock，但sendmail 模拟的called和called_args属性未正确更新。看来我没有正确应用补丁。这是我正在尝试的一个简化示例：import unittest.mockwith unittest.mock.patch('smtplib.SMTP', autospec=True) as mock:    import smtplib    smtp = smtplib.SMTP('localhost')    smtp.sendmail('me', 'me', 'hello world\n')    mock.assert_called()           # <--- this succeeds    mock.sendmail.assert_called()  # <--- this fails此示例生成：AssertionError: Expected 'sendmail' to have been called.如果我将补丁更改为smtp.SMTP.sendmail；例如：with unittest.mock.patch('smtplib.SMTP.sendmail.', autospec=True) as mock:    ...在这种情况下，我可以成功访问模拟的called_args和属性，但由于允许进行初始化，因此与主机建立了实际的 smtp 会话。这是单元测试，我不希望发生实际的网络。calledsmtplib.SMTP

Answer 1

我今天遇到了同样的问题，忘记了我正在使用上下文，所以只需更改

mock.sendmail.assert_called()

到

mock.return_value.__enter__.return_value.sendmail.assert_called()

这看起来很混乱，但这是我的例子：

msg = EmailMessage()

msg['From'] = '[e-mail]'

msg['To'] = '[e-mail]'

msg['Subject'] = 'subject'

msg.set_content('content');

with patch('smtplib.SMTP', autospec=True) as mock_smtp:

    misc.send_email(msg)

    mock_smtp.assert_called()

    context = mock_smtp.return_value.__enter__.return_value

    context.ehlo.assert_called()

    context.starttls.assert_called()

    context.login.assert_called()

    context.send_message.assert_called_with(msg)

Answer 2

我将 Dustymugs 的帖子标记为答案，但我发现了另一种技术来对依赖于模拟 method_calls 的调用进行单元测试。

import unittest.mock

with unittest.mock.patch('smtplib.SMTP', autospec=True) as mock:

    import smtplib

    smtp = smtplib.SMTP('localhost')

    smtp.sendmail('me', 'you', 'hello world\n')

    # Validate sendmail() was called

    name, args, kwargs = smtpmock.method_calls.pop(0)

    self.assertEqual(name, '().sendmail')

    self.assertEqual({}, kwargs)

    # Validate the sendmail() parameters

    from_, to_, body_ = args

    self.assertEqual('me', from_)

    self.assertEqual(['you'], to_)

    self.assertIn('hello world', body_)