assertSequenceEqual does not use _getAssertEqualityFunc

[Rarity]

BPO	44819
Nosy	@rbtcollins, @ezio-melotti, @voidspace, @iritkatriel, @jdevries3133
Superseder	bpo-22452: addTypeEqualityFunc is not used in assertListEqual
Files	example.py

^{Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.}

Show more details

GitHub fields:

assignee = None
closed_at = <Date 2021-08-07.19:03:39.580>
created_at = <Date 2021-08-03.20:24:40.648>
labels = ['type-bug', 'tests', '3.9']
title = 'assertSequenceEqual does not use _getAssertEqualityFunc'
updated_at = <Date 2021-08-07.19:03:39.579>
user = 'https://bugs.python.org/Rarity'

bugs.python.org fields:

activity = <Date 2021-08-07.19:03:39.579>
actor = 'iritkatriel'
assignee = 'none'
closed = True
closed_date = <Date 2021-08-07.19:03:39.580>
closer = 'iritkatriel'
components = ['Tests']
creation = <Date 2021-08-03.20:24:40.648>
creator = 'Rarity'
dependencies = []
files = ['50201']
hgrepos = []
issue_num = 44819
keywords = []
message_count = 5.0
messages = ['398851', '398860', '398891', '398911', '399198']
nosy_count = 6.0
nosy_names = ['rbcollins', 'ezio.melotti', 'michael.foord', 'iritkatriel', 'jack__d', 'Rarity']
pr_nums = []
priority = 'normal'
resolution = 'duplicate'
stage = 'resolved'
status = 'closed'
superseder = '22452'
type = 'behavior'
url = 'https://bugs.python.org/issue44819'
versions = ['Python 3.6', 'Python 3.9']

[Rarity]

Like the title says, TestCase.assertSequenceEqual does not behave like TestCase.assertEqual where it uses TestCase._getAssertEqualityFunc. Instead, TestCase.assertSequenceEqual uses item1 != item2. That way I can do something like this:

def test_stuff(self):
   self.addTypeEqualityFunc(
      MyObject,
      comparison_method_which_compares_how_i_want,
   )
   self.assertListEqual(
      get_list_of_objects(),
      [MyObject(...), MyObject(...)],
   )

[jdevries3133]

Brian, can you be more specific about what problem is caused by the fact that assertSequenceEqual does not use _getAssertEqualityFunc? Also, I'm not sure what your example is trying to demonstrate. Can you provide a minimal example that shows the problem, but also defines what MyObject, etc. are?

Let me know if I'm missing something.

[iritkatriel]

That's correct, and apparently not mentioned in the doc: https://docs.python.org/3/library/unittest.html#unittest.TestCase.assertSequenceEqual

[Rarity]

I've attached an example of what I want. It contains a class, a function to be tested, and a test class which tests the function.

What TestCase.addTypeEqualityFunc feels like it offers is a chance to compare objects however I feel like is needed for each test. Sometimes all I want is to compare the properties of the objects, and maybe not even all of the properties! When I have a list of these objects and I've added an equality function for the object, I was expecting the test class to use my equality function when comparing objects in the list.

[iritkatriel]

Closing as duplicate of bpo-22452.