def test_ray_from_below():
p = Plane()
r = Ray(Point(0, -1, 0), Vector(0, 1, 0))
xs = p.local_intersect(r)
assert len(xs) == 1
assert xs[0].t == 1
assert xs[0].object == p
def test_intersect_from_above(self):
p = Plane()
r = Ray(Point(0, -1, 0), Vector(0, 1, 0))
xs = p.local_intersect(r)
self.assertEqual(len(xs), 1)
self.assertEqual(xs[0].t, 1)
self.assertEqual(xs[0].object, p)
def test_coplanar_ray():
p = Plane()
r = Ray(Point(0, 0, 0), Vector(0, 0, 1))
xs = p.local_intersect(r)
assert len(xs) == 0
def test_intersect_with_coplanar(self):
p = Plane()
r = Ray(Point(0, 0, 0), Vector(0, 0, 1))
xs = p.local_intersect(r)
self.assertEqual(len(xs), 0)