def test_update_motion_returns_same_position_for_no_velocity_or_accel(
self):
testObj = Particle(self.positionList)
dtime = 10
testObj.update_motion(dtime)
expected_position = self.positionList
actual_position = testObj.position
np.testing.assert_equal(expected_position, actual_position)
def test_update_motion_returns_expected_position_for_given_velocity(self):
testObj = Particle(self.positionList, self.velocity)
expected_position = np.array(self.positionList)
constant_velocity = np.array(self.velocity)
dtime = 10
testObj.update_motion(10)
expected_position = expected_position + (constant_velocity * dtime)
actual_position = testObj.position
np.testing.assert_equal(expected_position, actual_position)
def test_update_motion_returns_expected_position_and_velocity_for_given_accel(
self):
testObj = Particle(self.positionList, self.velocity, self.acceleration)
expected_position = np.array(self.positionList)
initial_velocity = np.array(self.velocity)
acceleration = np.array(self.acceleration)
dtime = 10
testObj.update_motion(10)
expected_position = (expected_position + (initial_velocity * dtime) +
(acceleration * (dtime**2)) / 2)
expected_velocity = initial_velocity + (acceleration * dtime)
actual_position = testObj.position
actual_velocity = testObj.velocity
np.testing.assert_equal(expected_position, actual_position)
np.testing.assert_equal(expected_velocity, actual_velocity)