def test_calculate_fitness_range():
"""Fitness should always be in this interval: (0,1)"""
for number in range(1, 100):
h1 = Herbivore(age=number, weight=number)
assert 0 < h1.calculate_fitness() < 1
def test_calculate_fitness_negative_weight():
"""Does negative weight give fitness: 0?"""
h1 = Herbivore(weight=-1)
assert h1.calculate_fitness() == 0
