def test_ageing():
"""Test that the both herbivore and carnivore ages by 1 year each time called."""
herb = Herbivore(10, 20)
carn = Carnivore(10, 20)
herb.aging()
carn.aging()
assert herb.age == 11
assert carn.age == 11
def test_fitness_aging():
"""Test that the fitness changes with age."""
herb = Herbivore(5, 10)
fitness_before_herbivore = herb.fitness
carn = Carnivore(5, 30)
fitness_before_carnivore = carn.fitness
herb.aging()
carn.aging()
fitness_after_herbivore = herb.fitness
fitness_after_carnivore = carn.fitness
assert fitness_before_herbivore != fitness_after_herbivore
assert fitness_before_carnivore != fitness_after_carnivore
