@Test
public void testAdd() {

  final ColorRGBA clr1 = new ColorRGBA(ColorRGBA.BLACK_NO_ALPHA);
  final ColorRGBA clr2 = new ColorRGBA(ColorRGBA.WHITE);
  clr1.addLocal(1, 2, 3, 4);
  assertEquals(new ColorRGBA(1, 2, 3, 4), clr1);
  clr1.addLocal(-1, -2, -3, -4);
  assertEquals(ColorRGBA.BLACK_NO_ALPHA, clr1);
  clr1.zero();
  clr1.addLocal(clr2);
  assertEquals(ColorRGBA.WHITE, clr1);
  clr1.zero();
  final ColorRGBA clr3 = clr1.add(clr2, new ColorRGBA());
  assertEquals(ColorRGBA.BLACK_NO_ALPHA, clr1);
  assertEquals(ColorRGBA.WHITE, clr3);
  final ColorRGBA clr4 = clr1.add(0, 0, 0, 1, null);
  assertEquals(ColorRGBA.BLACK_NO_ALPHA, clr1);
  assertEquals(ColorRGBA.BLACK, clr4);
}