  class OptionalRelationModel(RESTFrameworkModel):
      other = models.ForeignKey('OptionalRelationModel', blank=True, null=True)
  
  
  # Model for issue #725
  class SeveralChoicesModel(RESTFrameworkModel):
      color = models.CharField(
          max_length=10,
          choices=[('red', 'Red'), ('green', 'Green'), ('blue', 'Blue')],
          blank=False
      )
      drink = models.CharField(
          max_length=10,
          choices=[('beer', 'Beer'), ('wine', 'Wine'), ('cider', 'Cider')],
          blank=False,
          default='beer'
      )
      os = models.CharField(
          max_length=10,
          choices=[('linux', 'Linux'), ('osx', 'OSX'), ('windows', 'Windows')],
          blank=True
      )
      music_genre = models.CharField(
          max_length=10,
          choices=[('rock', 'Rock'), ('metal', 'Metal'), ('grunge', 'Grunge')],
          blank=True,
          default='metal'
      )
  
  
  # Model for RegexField
  class Book(RESTFrameworkModel):
      isbn = models.CharField(max_length=13)
  
  
 
</s> remove     ManyToManyModel, Person, ReadOnlyManyToManyModel, Photo, SeveralChoicesModel)
 </s> add     ManyToManyModel, Person, ReadOnlyManyToManyModel, Photo)
  class OptionalRelationModel(RESTFrameworkModel):
      other = models.ForeignKey('OptionalRelationModel', blank=True, null=True)
  
  


























  # Model for RegexField
  class Book(RESTFrameworkModel):
      isbn = models.CharField(max_length=13)
  
  
keep keep keep keep replace replace replace replace replace replace replace replace replace replace replace replace replace replace replace replace replace replace replace replace replace replace replace replace replace replace keep keep keep keep keep
 Moved test model into closer to the testcase 
rest_framework/tests/models.py