There used to be a [bug in Django](https://code.djangoproject.com/ticket/30427)
that caused these tests to fail, according to the discussion of #370.
That bug was fixed in Django 4.0.
However, because the test model was using a `FieldTracker`
rather than a `ModelTracker`, all model-specific test cases
in `ModelTrackerTests` continued to fail.
Avoid using `Self` as a type argument: for some reason this fails
when mypy has an empty cache, but passes when the cache has been
filled. Maybe it's a weird interaction between the mypy core and
the django-stubs plugin?
The decorator works without an argument as well, but that is an
undocumented feature of `unittest.skip()` that is not understood
by mypy and pytest.
In the case of pytest, it ignored the decorated class during test
collection, instead of collecting it and marking it as skipped.
* add test for reproducing FieldTracker update_fields issue
FieldTracker does not see update_fields changed in tracked model.save() method
* Patch Model.save_base instead of save
This change allows proper capturing update_fields kwarg if is is changed in overridden save() method.
* Add some details about FieldTracker implementation
* Mention FieldTracker behavior change
* - add django 3.0 to the test matrix
- drop six
* add entry in CHANGES
* remove context kwarg
* fix test with DeferredAttribute
* rename StringyDescriptor's name to attname
* Fix flake8
* Drop support for Django 1.11 because the API are not compatibles anymore with Django 3.0
* Try to fix tests.
* Define model for the field mock.
* Simplifies the code.
* Properly mock the field.
* Typo
* Use the new API field name.
* Call it attname
* Grab the field instance from the model.
* Use postgres in travis tests.
* Django 2.0.1 minimum is needed.
* Update Changelog to tell about breaking Django 1.11.
* Update changelog to tell about Django 3.0 support.
* @natim review.
This commit adds a collection of wrapper classes for tracking fields
while still using custom descriptors that may be present. This fixes
a bug where deferring a model field with a custom descriptor meant
that the descriptor was overridden in all subsequent queries.
