如何在Django單元測試中正確使用assertRaises？

Question

問題非常簡單：我不能在Django 1.5單元測試中使用self.assertRaises。

我真的想驗證當您嘗試從不存在的數據庫中刪除提供程序時，會引發LookupError。

如您所見，我有一個ProviderDAO類，我在其中定義了如何刪除提供程序。 然后我只在單元測試類ProviderManagerTests中調用此方法delete_provider（）。 我已經概述了代碼中的所有可能性，此時我來到這里尋求答案（我已經閱讀了相關問題中的建議，但沒有做到這一點）我正在使用python 2.7.5謝謝！

class ProviderManager(models.Manager):
   def delete_provider(self, provider_id):
        matching_providers = Provider.objects.filter(providerId=provider_id)
        print 'delete provider method matching providers %s ' % matching_providers
        print 'delete provider method matching providers %s ' % matching_providers.count()
        if matching_providers.count() > 0:
            matching_providers.delete()
        elif matching_providers.count() == 0:
            raise LookupError('No deletion; no providers matching this id')

class ProviderManagerTests(TestCase):
    def test_delete_nonexistent_provider(self):
        provider_manager = ProviderManager()
        someRoles = Role(name='boss')
        someRoles.save()
        someSpecialties = Specialty(name='senior care')
        someSpecialties.save()
        provider_manager.delete_provider('398236503462063')
        #self.assertIsNone(provider,'provider should be none')
        #self.assertTrue(Provider.objects.filter(providerId='123456') == 0)
        ###self.assertRaises(LookupError,provider_manager.delete_provider, providerId='398236503462063')
        #self.assertRaises(LookupError,provider_manager.delete_provider, provider_id='398236503462063')
        #self.assertRaises(LookupError,lambda: provider_manager.delete_provider,provider_id='234234234')
        #self.assertRaises(LookupError,lambda: provider_manager.delete_provider(provider_id='234234234'))
        # with self.assertRaises(LookupError):
        #     provider_manager.delete_provider(provider_id='398236503462063')

        with self.assertRaises(LookupError):
            provider_manager.delete_provider('398236503462063')

和堆棧軌道：

======================================================================
ERROR: test_delete_nonexistent_provider (edu.tests.ProviderTests)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/Users/tests.py", line 68, in test_delete_nonexistent_provider
    provider_manager.delete_provider('398236503462063')
  File "/Users/models.py", line 92, in delete_provider
    raise LookupError('No deletion; no providers matching this id')
LookupError: No deletion; no providers matching this id

----------------------------------------------------------------------
Ran 14 tests in 0.306s

FAILED (errors=1)

Answer 1

順便說一下，你可以這樣寫：

self.assertRaises(LookupError, provider_manager.delete_provider, '398236503462063')