DefaultedPets valid {}: accepted
DefaultedPets valid {"pet": {"type": "cat"}}: accepted
DefaultedPets valid {"pet": {"type": "dog"}}: accepted
DefaultedPets valid {"pet": {"type": "bird"}}: accepted
DefaultedPets invalid {"pet": {"type": "fish"}}: rejected
DefaultedPets invalid {"pet": "cat"}: rejected
DefaultedPets invalid {"pet": {}}: rejected
