@Test
public void testSimpleHash() {

  // Just a simple sanity check.
  final Triangle tri1 = new Triangle(Vector3.ZERO, Vector3.UNIT_Y, Vector3.NEG_ONE, 1);
  final Triangle tri2 = new Triangle(Vector3.ZERO, Vector3.UNIT_Y, Vector3.NEG_ONE, 1);
  final Triangle tri3 = new Triangle(Vector3.ZERO, Vector3.UNIT_Z, Vector3.NEG_ONE, 2);
  assertTrue(tri1.hashCode() == tri2.hashCode());
  assertTrue(tri1.hashCode() != tri3.hashCode());
}