def test_no_birth_if_baby_weight_is_zero(self, example_properties_w_40,
mocker):
"""
Tests birth_process method.
Asserts that no baby is born if the baby's birth weight is
equal to zero.
"""
mocker.patch('numpy.random.normal', return_value=0)
animal = Animal(example_properties_w_40)
animal.find_fitness()
assert animal.birth_process(num_animals=6) is None
def test_no_birth_when_mothers_weight_small(self, example_properties_w_40,
mocker):
"""
Asserts that no baby is born from running birth_process
when mother's weight is less than xi times baby's weight.
"""
mocker.patch('numpy.random.normal', return_value=50)
animal = Animal(example_properties_w_40)
animal.find_fitness()
baby_weight = animal.birth_process(num_animals=6)
assert baby_weight is None
def test_mother_loses_weight_after_birth(self, example_properties_w_40,
mocker):
"""
Test birth_process method.
Asserts that mother loses weight equal to xi * baby's weight after
giving birth.
"""
mocker.patch('numpy.random.normal', return_value=5.5)
animal = Animal(example_properties_w_40)
animal.find_fitness()
initial_weight = animal.weight
birth_weight = animal.birth_process(num_animals=6)
assert animal.weight == initial_weight - \
(animal.params['xi'] * birth_weight)
def test_baby_weight_returned_when_mothers_weight_large_enough(
self, example_properties_w_40, mocker):
"""
After running birth_process, we check that a birth took place by
testing if baby's weight is a float of given value and that the baby's
weight times xi was smaller than the mother's weight.
"""
mocker.patch('numpy.random.normal', return_value=5.5)
animal = Animal(example_properties_w_40)
animal.find_fitness()
baby_weight = animal.birth_process(num_animals=6)
assert type(baby_weight) is float
assert baby_weight == 5.5
assert animal.weight > baby_weight * animal.params['xi']