django model enum choices

enum_choices.py

from enum import Enum


class Choices(Enum):
    """
    Helper to construct choices for django Model or Form fields.

        class Animals(Choices):
            DOG = 'dog'
            CAT = 'cat'

        class Vet(models.Model):
            client = models.CharField(
                choices=Animals.choices(),
                max_length=Animals.max_length(),
                default=Animals.DOG
            )
    """

    def __eq__(self, other):
        if other is self:
            return True
        elif other == str(self):
            # support asteroid.state == AsteroidState.DELETED
            #          (str from db)     (actual enum value)
            return True
        else:
            return False

    @classmethod
    def max_length(cls):
        return max(len(c[0]) for c in cls.choices())

    @classmethod
    def choices(cls):
        return ((str(c), c.value) for c in cls)


class Animals(Choices):
    DOGGO = 'dog'
    CATTO = 'cat'
    CROCO = 'crocodile'
    GIRAFFE = 'giraffe'


def test_choices_max_length():
    assert Animals.max_length() == 15


def test_choices_choices():
    assert list(Animals.choices()) == [
        ('Animals.DOGGO', 'dog'),
        ('Animals.CATTO', 'cat'),
        ('Animals.CROCO', 'crocodile'),
        ('Animals.GIRAFFE', 'giraffe'),
    ]


def test_choices_equality():
    assert Animals.GIRAFFE == 'Animals.GIRAFFE'
    assert Animals.GIRAFFE != 'Animals.CROCO'
    assert Animals.GIRAFFE == Animals.GIRAFFE
    assert Animals.GIRAFFE != Animals.CROCO


def test_choices_access():
    assert str(Animals.GIRAFFE) in (c[0] for c in Animals.choices())