Django 的 assertQuerysetEqual() 方法失败，尽管两个查询集在 shell?

Question

我有一个 Family 和一个具有一对多关系的 Session，这样一个实例 family 就有一个 session_set。此外，Session 有一个 session_number 字段，它是一个整数。

我有两个 Family、family1 和 family2 的实例，这样如果我在 ipdb 调试器中打印出它们的 session_set.order_by('session_number') 我得到它们看起来完全一样：

ipdb> family1.session_set.order_by('session_number')
<QuerySet [<Session: Welcome>, <Session: First-Time Parents: The Basics of Birth>, <Session: Initial Postpartum Lactation>, <Session: Sleep Techniques for New Babies>, <Session: Breastfeeding Preparation>, <Session: Newborn Care Basics>, <Session: Easing the Transition Back to Work>, <Session: Preparing for Parenting>, <Session: Decoding Baby Cues>, <Session: Postpartum Doula Support>, <Session: First-Time Parents: Birth Prep Q&A>, <Session: Postpartum Lactation Follow-Up>, <Session: Sleep Training for 4 Months & Beyond>, <Session: Mental Wellness in Pregnancy>, <Session: Infant CPR>, <Session: Prenatal Pelvic Physical Therapy>, <Session: Prenatal Massage>]>
ipdb> family2.session_set.order_by('session_number')
<QuerySet [<Session: Welcome>, <Session: First-Time Parents: The Basics of Birth>, <Session: Initial Postpartum Lactation>, <Session: Sleep Techniques for New Babies>, <Session: Breastfeeding Preparation>, <Session: Newborn Care Basics>, <Session: Easing the Transition Back to Work>, <Session: Preparing for Parenting>, <Session: Decoding Baby Cues>, <Session: Postpartum Doula Support>, <Session: First-Time Parents: Birth Prep Q&A>, <Session: Postpartum Lactation Follow-Up>, <Session: Sleep Training for 4 Months & Beyond>, <Session: Mental Wellness in Pregnancy>, <Session: Infant CPR>, <Session: Prenatal Pelvic Physical Therapy>, <Session: Prenatal Massage>]>

但是，如果我将这些查询集输入 assertQuerysetEqual，我会得到一个测试失败：

ipdb> self.assertQuerysetEqual(family1.session_set.order_by('session_number'), family2.session_set.order_by('session_number'))
*** AssertionError: Lists differ: ['<Session: Welcome>', '<Session: First-Ti[642 chars]ge>'] != [<Session: Welcome>, <Session: First-Time [608 chars]age>]

First differing element 0:
'<Session: Welcome>'
<Session: Welcome>

Diff is 2186 characters long. Set self.maxDiff to None to see it.

这里是 maxDiff 设置为 None 的更详细的比较：

ipdb> self.maxDiff = None
ipdb> self.assertQuerysetEqual(family1.session_set.order_by('session_number'), family2.session_set.order_by('session_number'))
*** AssertionError: Lists differ: ['<Session: Welcome>', '<Session: First-Ti[642 chars]ge>'] != [<Session: Welcome>, <Session: First-Time [608 chars]age>]

First differing element 0:
'<Session: Welcome>'
<Session: Welcome>

- ['<Session: Welcome>',
?  -                  -

+ [<Session: Welcome>,
-  '<Session: First-Time Parents: The Basics of Birth>',
?  -                                                  -

+  <Session: First-Time Parents: The Basics of Birth>,
-  '<Session: Initial Postpartum Lactation>',
?  -                                       -

+  <Session: Initial Postpartum Lactation>,
-  '<Session: Sleep Techniques for New Babies>',
?  -                                          -

+  <Session: Sleep Techniques for New Babies>,
-  '<Session: Breastfeeding Preparation>',
?  -                                    -

+  <Session: Breastfeeding Preparation>,
-  '<Session: Newborn Care Basics>',
?  -                              -

+  <Session: Newborn Care Basics>,
-  '<Session: Easing the Transition Back to Work>',
?  -                                             -

+  <Session: Easing the Transition Back to Work>,
-  '<Session: Preparing for Parenting>',
?  -                                  -

+  <Session: Preparing for Parenting>,
-  '<Session: Decoding Baby Cues>',
?  -                             -

+  <Session: Decoding Baby Cues>,
-  '<Session: Postpartum Doula Support>',
?  -                                   -

+  <Session: Postpartum Doula Support>,
-  '<Session: First-Time Parents: Birth Prep Q&A>',
?  -                                             -

+  <Session: First-Time Parents: Birth Prep Q&A>,
-  '<Session: Postpartum Lactation Follow-Up>',
?  -                                         -

+  <Session: Postpartum Lactation Follow-Up>,
-  '<Session: Sleep Training for 4 Months & Beyond>',
?  -                                               -

+  <Session: Sleep Training for 4 Months & Beyond>,
-  '<Session: Mental Wellness in Pregnancy>',
?  -                                       -

+  <Session: Mental Wellness in Pregnancy>,
-  '<Session: Infant CPR>',
?  -                     -

+  <Session: Infant CPR>,
-  '<Session: Prenatal Pelvic Physical Therapy>',
?  -                                           -

+  <Session: Prenatal Pelvic Physical Therapy>,
-  '<Session: Prenatal Massage>']
?  -                           -

+  <Session: Prenatal Massage>]

比较好像是'out of sync'。然而，session_number也是一样的：

ipdb> [(session.session_number, str(session.session_type)) for session in family1.session_set.order_by('session_number')]
[(0, 'Welcome'), (1, 'First-Time Parents: The Basics of Birth'), (2, 'Initial Postpartum Lactation'), (3, 'Sleep Techniques for New Babies'), (4, 'Breastfeeding Preparation'), (5, 'Newborn Care Basics'), (6, 'Easing the Transition Back to Work'), (7, 'Preparing for Parenting'), (8, 'Decoding Baby Cues'), (9, 'Postpartum Doula Support'), (10, 'First-Time Parents: Birth Prep Q&A'), (11, 'Postpartum Lactation Follow-Up'), (12, 'Sleep Training for 4 Months & Beyond'), (13, 'Mental Wellness in Pregnancy'), (14, 'Infant CPR'), (15, 'Prenatal Pelvic Physical Therapy'), (16, 'Prenatal Massage')]
ipdb> [(session.session_number, str(session.session_type)) for session in family2.session_set.order_by('session_number')]
[(0, 'Welcome'), (1, 'First-Time Parents: The Basics of Birth'), (2, 'Initial Postpartum Lactation'), (3, 'Sleep Techniques for New Babies'), (4, 'Breastfeeding Preparation'), (5, 'Newborn Care Basics'), (6, 'Easing the Transition Back to Work'), (7, 'Preparing for Parenting'), (8, 'Decoding Baby Cues'), (9, 'Postpartum Doula Support'), (10, 'First-Time Parents: Birth Prep Q&A'), (11, 'Postpartum Lactation Follow-Up'), (12, 'Sleep Training for 4 Months & Beyond'), (13, 'Mental Wellness in Pregnancy'), (14, 'Infant CPR'), (15, 'Prenatal Pelvic Physical Therapy'), (16, 'Prenatal Massage')]

为什么 assertQuerysetEqual 没有按预期工作？

Answer 1

这是因为 assertQuerysetEqual 不会将查询集与另一个查询集进行比较，而是将查询集与值列表进行比较。

来自assertQuerysetEqual's documentation：

TransactionTestCase.assertQuerysetEqual(qs, values, transform=repr, ordered=True, msg=None)

Asserts that a queryset qs returns a particular list of values values.

The comparison of the contents of qs and values is performed using the function transform; by default, this means that the repr() of each value is compared.

因此您应该将第二个参数转换为列表：

self.assertQuerysetEqual(family1.session_set.order_by('session_number'), list(family2.session_set.order_by('session_number')))

Answer 2

这对我有用：

self.assertQuerysetEqual(qs1, map(repr, qs2), ordered=False)

仅将第二个查询集转换为列表是不够的，因为引号仍然存在。在每个对象上调用 repr 是使值匹配的原因。