          self.assertEqual(list(ImprovedArticleForm.base_fields), ['article'])
  
          self.assertEqual(list(ImprovedArticleWithParentLinkForm.base_fields), [])
  
          bw = BetterWriter(name='Joe Better', score=10)
          bw.save()
          self.assertEqual(sorted(model_to_dict(bw)),
                           ['id', 'name', 'score', 'writer_ptr'])
  
          form = BetterWriterForm({'name': 'Some Name', 'score': 12})
          self.assertEqual(form.is_valid(), True)
 
</s> remove         self.assertEqual(form.is_valid(), True)
 </s> add         self.assertTrue(form.is_valid()) </s> remove         self.assertEqual(list(ImprovedArticleForm.base_fields), ['article'])
 </s> add         class ImprovedArticleWithParentLinkForm(forms.ModelForm):
            class Meta:
                model = ImprovedArticleWithParentLink
                fields = '__all__' </s> remove         bw2.delete()
 </s> add         self.assertEqual(bw2.score, 12)

    def test_onetoonefield(self):
        class WriterProfileForm(forms.ModelForm):
            class Meta:
                # WriterProfile has a OneToOneField to Writer
                model = WriterProfile
                fields = '__all__'

        self.w_royko = Writer.objects.create(name='Mike Royko')
        self.w_woodward = Writer.objects.create(name='Bob Woodward') </s> remove         # OneToOneField ###############################################################
 </s> add     # OneToOneField ###############################################################
    def test_modelform_onetoonefield(self):
        class ImprovedArticleForm(forms.ModelForm):
            class Meta:
                model = ImprovedArticle
                fields = '__all__'
    def test_modelform_subclassed_model(self):
        class BetterWriterForm(forms.ModelForm):
            class Meta:
                # BetterWriter model is a subclass of Writer with an additional `score` field
                model = BetterWriter
                fields = '__all__'

        bw = BetterWriter.objects.create(name='Joe Better', score=10)
          self.assertEqual(list(ImprovedArticleForm.base_fields), ['article'])
  
          self.assertEqual(list(ImprovedArticleWithParentLinkForm.base_fields), [])
  
    def test_modelform_subclassed_model(self):
        class BetterWriterForm(forms.ModelForm):
            class Meta:
                # BetterWriter model is a subclass of Writer with an additional `score` field
                model = BetterWriter
                fields = '__all__'

        bw = BetterWriter.objects.create(name='Joe Better', score=10)
    def test_modelform_subclassed_model(self):
        class BetterWriterForm(forms.ModelForm):
            class Meta:
                # BetterWriter model is a subclass of Writer with an additional `score` field
                model = BetterWriter
                fields = '__all__'

        bw = BetterWriter.objects.create(name='Joe Better', score=10)
          self.assertEqual(sorted(model_to_dict(bw)),
                           ['id', 'name', 'score', 'writer_ptr'])
  
          form = BetterWriterForm({'name': 'Some Name', 'score': 12})
          self.assertEqual(form.is_valid(), True)
keep keep keep keep replace replace keep keep keep keep keep
 Fixed #6103 -- Splitted tests in model_forms tests 
tests/model_forms/tests.py