@Test
public void testSubtract() {

  final Vector3 vec1 = new Vector3();
  final Vector3 vec2 = new Vector3(Vector3.ONE);
  vec1.subtractLocal(1, 2, 3);
  assertEquals(new Vector3(-1, -2, -3), vec1);
  vec1.subtractLocal(-1, -2, -3);
  assertEquals(Vector3.ZERO, vec1);
  vec1.zero();
  vec1.subtractLocal(vec2);
  assertEquals(Vector3.NEG_ONE, vec1);
  vec1.zero();
  final Vector3 vec3 = vec1.subtract(vec2, new Vector3());
  assertEquals(Vector3.ZERO, vec1);
  assertEquals(Vector3.NEG_ONE, vec3);
  final Vector3 vec4 = vec1.subtract(1, 0, 0, null);
  assertEquals(Vector3.ZERO, vec1);
  assertEquals(Vector3.NEG_UNIT_X, vec4);
}