尝试将非有序查询集与多个有序值django进行比较

Question

此单元测试失败,但以下情况除外:

def test_vote_form_with_multiple_choices_allowed_and_submitted(self):
    """
    If multiple choices are allowed and submitted, the form should be valid.
    """
    vote_form = VoteForm({'choice': [1, 2]}, instance=create_question('Dummy question', -1,
                                                                      [Choice(choice_text='First choice'), Choice(
                                                                          choice_text='Second choice')],
                                                                      allow_multiple_choices=True))
    self.assertTrue(vote_form.is_valid())
    self.assertQuerysetEqual(vote_form.cleaned_data['choice'], ['<Choice: First choice>', '<Choice: Second choice>'])

ValueError:尝试将非有序查询集与多个有序值进行比较我做错了什么？

Answer 1

来自docs:

默认情况下,比较也依赖于排序.如果qs不提供隐式排序,则可以将ordered参数设置为False,从而将比较转换为collections.Counter比较.如果订单未定义(如果给定的qs未排序且比较针对多个有序值),则会引发ValueError.

你正在比较a QuerySet和a list.List有一个排序,但Queryset没有.

因此,您可以将QuerySet转换为列表

queryset = vote_form.cleaned_data['choice']
self.assertQuerysetEqual(list(queryset), ['<Choice: First choice>', ...])

或传递ordered=False给assertQuerysetEqual.

queryset = vote_form.cleaned_data['choice']
self.assertQuerysetEqual(list(queryset), ['<Choice: First choice>', ...], ordered=False)

在比较之前重新排序Queryset也应该有效.