'Ensure that the correct list of super classes is assembled when
importing part of the model.'

def test_external_superclasses(self):

    class Animal(Base, ):
        pass
    class Fish(Animal, ):
        pass
    class Guppy(Fish, ):
        pass
    class Mammal(Animal, ):
        pass
    class Dog(Mammal, ):
        pass
    class Human(Mammal, ):
        pass
    self.assertEqual(Animal._superclasses, ('Base',))
    self.assertEqual(Fish._superclasses, ('Base', 'Base.Animal'))
    self.assertEqual(Guppy._superclasses, ('Base', 'Base.Animal', 'Base.Animal.Fish'))
    self.assertEqual(Mammal._superclasses, ('Base', 'Base.Animal'))
    self.assertEqual(Dog._superclasses, ('Base', 'Base.Animal', 'Base.Animal.Mammal'))
    self.assertEqual(Human._superclasses, ('Base', 'Base.Animal', 'Base.Animal.Mammal'))
