Opened 17 months ago
Closed 14 months ago
#34657 closed New feature (fixed)
Testing assertions `assertContains` and `assertInHTML` should output the haystack on failure
Reported by: | Thibaud Colas | Owned by: | Chinmoy |
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Component: | Testing framework | Version: | dev |
Severity: | Normal | Keywords: | HTML, assertions, testing |
Cc: | Chinmoy | Triage Stage: | Ready for checkin |
Has patch: | yes | Needs documentation: | no |
Needs tests: | no | Patch needs improvement: | no |
Easy pickings: | no | UI/UX: | no |
Description (last modified by )
If I use the vanilal Python assertIn
or assertRegex
, when the assertion fails, it’s very simple to assess what went wrong from the test error only:
self.assertIn("<b>hey</b>", "<p>Howdy!</p>") AssertionError: '<b>hey</b>' not found in '<p>Howdy!</p>'
With Django’s assertContains
and assertInHTML
, this gets much harder:
self.assertInHTML("<b>hey</b>", "<p>Howdy!</p>") File "/Users/thibaudcolas/Dev/django/html-testing-with-django/.venv/lib/python3.11/site-packages/django/test/testcases.py", line 1076, in assertInHTML self.assertTrue( AssertionError: False is not true : Couldn't find '<b> hey </b>' in response
and:
self.assertContains(res, "<b>hey</b>") File "/Users/thibaudcolas/Dev/django/html-testing-with-django/.venv/lib/python3.11/site-packages/django/test/testcases.py", line 660, in assertContains self.assertTrue( AssertionError: False is not true : Couldn't find '<b>hey</b>' in response
---
In both cases, Django doesn’t display the haystack – so I have to waste a lot of time going back to my HTML templates to check what they might be outputting / or potentially load the same scenario in a browser / or manually add print
statements to my test cases. This is all very time-consuming. Instead, it’d be much better if the haystack was just present.
Additionally for assertInHTML
– it’s annoying that needle
as displayed in the failure message is the parser’s output, which is therefore broken up over multiple lines. It’d be much nicer if the example above resulted in AssertionError: False is not true : Couldn't find '<b>hey</b>' in response
.
---
Test suite I used to compare output for reference: https://github.com/thibaudcolas/html-testing-with-django/blob/39c82c410cce4bea71ac54be27be67057f4d8dd8/testing_tests/tests.py#L5
And link to Python’s assertIn
/ assertNotIn
implementations: https://github.com/python/cpython/blob/101d5ec7d7fe122fa81a377c8ab8b562d1add9ee/Lib/unittest/case.py#L1147-L1159
Change History (25)
comment:1 by , 17 months ago
Description: | modified (diff) |
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follow-up: 4 comment:2 by , 17 months ago
Keywords: | testcases unit tests removed |
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Triage Stage: | Unreviewed → Accepted |
comment:3 by , 17 months ago
I can see the value of this. The react testing library we use has a setting DEBUG_PRINT_LIMIT
(https://testing-library.com/docs/dom-testing-library/api-debugging/#automatic-logging) with a default of 7000 characters but you can increase it if you need to see more printed. I recommend that we have a similar setting 👍
comment:4 by , 17 months ago
Replying to Sarah Boyce:
I can see the value of this. The react testing library we use has a setting
DEBUG_PRINT_LIMIT
(https://testing-library.com/docs/dom-testing-library/api-debugging/#automatic-logging) with a default of 7000 characters but you can increase it if you need to see more printed. I recommend that we have a similar setting 👍
Creating a new setting is always controversial (we already have many of them) and users can already control it with maxDiff
.
comment:5 by , 17 months ago
Sorry, I didn’t realise feature requests require a forum post! I’ll know for next time.
comment:6 by , 16 months ago
I have fixed this bug and sent a PR https://github.com/django/django/pull/17077 for consideration!)
comment:7 by , 16 months ago
Has patch: | set |
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Needs documentation: | set |
Needs tests: | set |
Patch needs improvement: | set |
comment:8 by , 16 months ago
Owner: | changed from | to
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Status: | new → assigned |
comment:9 by , 16 months ago
Resolution: | → fixed |
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Status: | assigned → closed |
comment:10 by , 16 months ago
Resolution: | fixed |
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Status: | closed → new |
Hi Shamil, we still need to review and merge in a PR before we mark a ticket as fixed. In general I would leave the status alone as mostly the fellows take care of this
I've written a couple of comments on the PR, once they're sorted we can update the ticket to go into the review queue
follow-up: 12 comment:11 by , 16 months ago
Hey, is this still being worked upon? Can I assign myself to this ticket?
comment:12 by , 16 months ago
Owner: | changed from | to
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Status: | new → assigned |
Replying to Chinmoy:
Hey, is this still being worked upon? Can I assign myself to this ticket?
Hi! Thank you for your interest in contributing. I checked and both related PRs are closed so if you can work on this, it'll be certainly welcomed! Thanks.
comment:13 by , 16 months ago
Has patch: | unset |
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Needs documentation: | unset |
Needs tests: | unset |
Patch needs improvement: | unset |
Resetting patch flags.
comment:14 by , 15 months ago
Cc: | added |
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comment:16 by , 15 months ago
Has patch: | set |
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Here is the PR https://github.com/django/django/pull/17204.
comment:17 by , 15 months ago
Needs documentation: | set |
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Patch needs improvement: | set |
Version: | → dev |
comment:18 by , 15 months ago
Needs documentation: | unset |
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Patch needs improvement: | unset |
comment:19 by , 15 months ago
Needs tests: | set |
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comment:20 by , 15 months ago
Needs tests: | unset |
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comment:22 by , 14 months ago
Patch needs improvement: | set |
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comment:24 by , 14 months ago
Patch needs improvement: | unset |
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Triage Stage: | Accepted → Ready for checkin |
Tentatively accepting because this is related to the testing framework, though I'm not 100% sure on procedure whether this specific case needs a forum post since it's marked as a new feature. I would argue this is a cleanup/optimization :thinking: