Fixed #31437 -- Corrected tests to show abstract multiple inheritance system check error.

Added minimal multiple inheritance test case showing error. Removed obsolete diamond-inheritance case, originally added in 85ef98d.

Author: carltongibson

tests/model_inheritance/test_abstract_inheritance.py

@@ -34,33 +34,30 @@ class DerivedGrandChild(AbstractDescendant):
  self.assertEqual(DerivedChild._meta.get_field('name').max_length, 50)
  self.assertEqual(DerivedGrandChild._meta.get_field('name').max_length, 50)
 
- def test_multiple_parents_mro(self):
- class AbstractBaseOne(models.Model):
- class Meta:
- abstract = True
-
- class AbstractBaseTwo(models.Model):
- name = models.CharField(max_length=30)
-
- class Meta:
- abstract = True
+ def test_multiple_inheritance_cannot_shadow_inherited_field(self):
+ class ParentA(models.Model):
+ name = models.CharField(max_length=255)
 
- class DescendantOne(AbstractBaseOne, AbstractBaseTwo):
  class Meta:
  abstract = True
 
- class DescendantTwo(AbstractBaseOne, AbstractBaseTwo):
- name = models.CharField(max_length=50)
+ class ParentB(models.Model):
+ name = models.IntegerField()
 
  class Meta:
  abstract = True
 
- class Derived(DescendantOne, DescendantTwo):
+ class Child(ParentA, ParentB):
  pass
 
- self.assertEqual(DescendantOne._meta.get_field('name').max_length, 30)
- self.assertEqual(DescendantTwo._meta.get_field('name').max_length, 50)
- self.assertEqual(Derived._meta.get_field('name').max_length, 50)
+ self.assertEqual(Child.check(), [
+ Error(
+ "The field 'name' clashes with the field 'name' from model "
+ "'model_inheritance.child'.",
+ obj=Child._meta.get_field('name'),
+ id='models.E006',
+ ),
+ ])
 
  def test_multiple_inheritance_cannot_shadow_concrete_inherited_field(self):
  class ConcreteParent(models.Model):