def METHOD_NAME(self):
    parts = self.system.part
    # try five times
    for i in range(5):
        self.system.part.all().pos = np.random.random(
            (len(self.system.part), 3)) * BOX_L
        self.assertAlmostEqual(
            np.min([self.system.distance([i, i, i], p.pos)
                    for p in parts]),
            self.dist_to_pos([i, i, i]), delta=1e-10)
        self.assertEqual(
            np.min([self.system.distance([i, i, i], p.pos)
                    for p in parts]),
            np.min([self.system.distance(p.pos, [i, i, i]) for p in parts]))