model_formsets tests added in r8528 fail on MySQL

[Karen Tracey <kmtracey@…>]

The model_formsets tests added in [8528] are failing on MySQL:

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FAIL: Doctest: modeltests.model_formsets.models.__test__.API_TESTS
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Traceback (most recent call last):
  File "/home/kmt/tmp/django/trunk/django/test/_doctest.py", line 2180, in runTest
    raise self.failureException(self.format_failure(new.getvalue()))
AssertionError: Failed doctest test for modeltests.model_formsets.models.__test__.API_TESTS
  File "/home/kmt/tmp/django/trunk/tests/modeltests/model_formsets/models.py", line unknown line number, in API_TESTS

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File "/home/kmt/tmp/django/trunk/tests/modeltests/model_formsets/models.py", line ?, in modeltests.model_formsets.models.__test__.API_TESTS
Failed example:
    for form in formset.forms:
        print form.as_p()
Expected:
    <p><label for="id_form-0-name">Name:</label> <input id="id_form-0-name" type="text" name="form-0-name" value="Ernest Hemingway" maxlength="100" /></p>
    <p><label for="id_form-0-write_speed">Write speed:</label> <input type="text" name="form-0-write_speed" value="10" id="id_form-0-write_speed" /><input type="hidden" name="form-0-author_ptr_id" value="4" id="id_form-0-author_ptr_id" /></p>
    <p><label for="id_form-1-name">Name:</label> <input id="id_form-1-name" type="text" name="form-1-name" maxlength="100" /></p>
    <p><label for="id_form-1-write_speed">Write speed:</label> <input type="text" name="form-1-write_speed" id="id_form-1-write_speed" /><input type="hidden" name="form-1-author_ptr_id" id="id_form-1-author_ptr_id" /></p>
Got:
    <p><label for="id_form-0-name">Name:</label> <input id="id_form-0-name" type="text" name="form-0-name" value="Ernest Hemingway" maxlength="100" /></p>
    <p><label for="id_form-0-write_speed">Write speed:</label> <input type="text" name="form-0-write_speed" value="10" id="id_form-0-write_speed" /><input type="hidden" name="form-0-author_ptr_id" value="5" id="id_form-0-author_ptr_id" /></p>
    <p><label for="id_form-1-name">Name:</label> <input id="id_form-1-name" type="text" name="form-1-name" maxlength="100" /></p>
    <p><label for="id_form-1-write_speed">Write speed:</label> <input type="text" name="form-1-write_speed" id="id_form-1-write_speed" /><input type="hidden" name="form-1-author_ptr_id" id="id_form-1-author_ptr_id" /></p>
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File "/home/kmt/tmp/django/trunk/tests/modeltests/model_formsets/models.py", line ?, in modeltests.model_formsets.models.__test__.API_TESTS
Failed example:
    formset.save()
Exception raised:
    Traceback (most recent call last):
      File "/home/kmt/tmp/django/trunk/django/test/_doctest.py", line 1267, in __run
        compileflags, 1) in test.globs
      File "<doctest modeltests.model_formsets.models.__test__.API_TESTS[64]>", line 1, in <module>
        formset.save()
      File "/home/kmt/tmp/django/trunk/django/forms/models.py", line 280, in save
        return self.save_existing_objects(commit) + self.save_new_objects(commit)
      File "/home/kmt/tmp/django/trunk/django/forms/models.py", line 294, in save_existing_objects
        obj = existing_objects[form.cleaned_data[self.model._meta.pk.attname]]
    KeyError: 4


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Ran 1 test in 0.253s

FAILED (failures=1)

For the first one the difference I notice is "value=4" (expected) vs. "value=5" (got) on the 2nd line. Probably the same problem causing the KeyError: 4 in the 2nd case -- some PK ID is turning out to be 5 on MySQL whereas it comes up 4 on the other backends? So the tests that look for value 4 and/or try to use that value are failing on MySQL?

[Malcolm Tredinnick]

Tracked this down to [8528] being the commit that started the failure (and the test in question wasn't added in that commit).

[Karen Tracey <kmtracey@…>]

Replying to mtredinnick:

Tracked this down to [8528] being the commit that started the failure (and the test in question wasn't added in that commit).

model_formsets overall wasn't added in that commit, but it is the stuff under

# Model inheritance in model formsets ######################################## 

added in that commit that is failing, right?

[Malcolm Tredinnick]

Yes, Karen's right. I looked at the first for-loop in that new section and saw it didn't match. But it's the second for-loop (searching for "Hemingway" was a better guess) over the formset that is breaking.

En passant, this isn't MySQL-specific. When running the full test suite for something else, I saw it fail identically with both PostgreSQL backends.

[Malcolm Tredinnick]

The problem here really is just with the test, not the code it's testing. The commit I'm about to make weakens the test for the precise characters in the form.as_p() output by avoiding the key value and then checks it's correct later on. We can't do a lot better than that with a doctest without writing something really messy, but all it hides is potential extra attributes being introduced, which isn't the sort of regression we've tended to make in that area.

[Malcolm Tredinnick]

(In [8563]) Fixed #8542 -- Made the model_formstests tests from [8528] a little less
dependent upon the precise values of auto-created primary key integers.

[Jacob]

Milestone 1.0 deleted