def test_set_force_throws_exception_for_zero_mass(self):
testObj = Particle(self.positionList,
acceleration=np.array(self.acceleration),
mass=0)
force = np.array([5.5, -3, 0.1])
with self.assertRaises(ValueError):
testObj.set_force(force)
def test_set_force_stores_expected_force_and_acceleration_value(self):
testObj = Particle(
self.positionList,
acceleration=np.array(self.acceleration),
mass=2.5,
)
force = np.array([5.5, -3, 0.1])
testObj.set_force(force)
expected_force = force
expected_acceleration = force / 2.5
actual_force = testObj.force
actual_acceleration = testObj.acceleration
np.testing.assert_equal(expected_force, actual_force)
np.testing.assert_equal(expected_acceleration, actual_acceleration)
def test_set_force_gives_zero_acceleration_for_infinite_mass(self):
testObj = Particle(
self.positionList,
acceleration=np.array(self.acceleration),
mass=np.inf,
)
force = np.array([5.5, -3, 0.1])
testObj.set_force(force)
expected_force = force
expected_acceleration = np.array([0, 0, 0])
actual_force = testObj.force
actual_acceleration = testObj.acceleration
np.testing.assert_equal(expected_force, actual_force)
np.testing.assert_equal(expected_acceleration, actual_acceleration)