@Test
public void testHashcode() {

    Color color1 = new Color(0.5, 0.5, 0.5);
    Color color2 = new Color(0.5, 0.5, 0.5);
    assertEquals(color1.hashCode(), color2.hashCode());
    color2 = new Color(0.5, 0.5, 0.6);
    assertNotEquals(color1.hashCode(), color2.hashCode());
}