walrus.py

import unittest
from chai import Chai

class Walrus(object):

    def __init__(self):
        self.energy = 0

    def receive_gift(self, gift):
        if gift.is_editable():
            self.energy += gift.digest().energy

class LifeEvent(object):

    def __init__(self, energy=0):
        self.energy = energy

class WalrusTestCase(Chai):

    def setUp(self):
        super(WalrusTestCase, self).setUp()
        self.subject = Walrus()

    def test_walrus_gains_enegery_by_eating_food(self):
        cheese = self.mock()

        self.expect(cheese.is_editable).returns(True)
        self.expect(cheese.digest).returns(LifeEvent(energy=100))
        self.subject.receive_gift(cheese)
        self.assert_equals(self.subject.energy, 100)
    
    def test_walrus_ignores_non_ediable_things(self):
        shoe = self.mock()

        self.expect(shoe.is_editable).returns(False)

        self.subject.receive_gift(shoe)
        self.assert_equals(self.subject.energy, 0)


if __name__ == "__main__":
    unittest.main()