def METHOD_NAME(self):
    a1 = np.array([0., 0., 0.])
    a2 = np.array([4., 4., 4.])
    b1 = np.array([4., 0., 0.])
    b2 = np.array([0., 4., 4.])
    p_intersect, vector1, vector2, vector3, vector4 = _intersection(a1, a2,
                                                                    b1, b2)
    # The value used for this test is computed by hand.
    self.assertTrue(np.allclose(p_intersect.flatten(), [2., 2., 2.],
                                atol=0.1))
    self.assertTrue(np.allclose(vector1, [0.58, -0.58, -0.58],
                                atol=0.1))
    self.assertTrue(np.allclose(vector2, [0.58, -0.58, -0.58],
                                atol=0.1))
    self.assertTrue(np.allclose(vector3, [0.58, 0.58, 0.58],
                                atol=0.1))
    self.assertTrue(np.allclose(vector4, [0.58, 0.58, 0.58],
                                atol=0.1))