def test_instantiation():
"""Verify that particles are created with correct attributes.
"""
p = elementary.Particle(1.0, 2.0, 3.0)
assert math.isclose(p.mass, 1.0)
assert all(math.isclose(*pos) for pos in zip(p.position, (1.0, 2.0, 3.0)) )
assert all(math.isclose(*mom) for mom in zip(p.momentum, (0.0, 0.0, 0.0)) )
def test_move():
"""Verify that motion proceeds as expected.
"""
p = elementary.Particle(1.0, 2.0, 3.0)
p.mass = 2.0 # Change mass so motion is nontrivial
p.impulse(1.0, 2.0, 3.0)
p.move(0.1)
assert all(math.isclose(*pos) for pos in zip(p.position, (1.0 + 0.1*1.0/2.0, 2.0 + 0.1*2.0/2.0, 3.0 + 0.1*3.0/2.0)) )
def test_impulse():
"""Verify that an impulse changes the momentum.
"""
p = elementary.Particle(1.0, 2.0, 3.0)
p.impulse(1.0, 2.0, 3.0)
assert all(math.isclose(*mom) for mom in zip(p.momentum, (1.0, 2.0, 3.0)) )