public boolean isValid() {
    return (mPrimaryColor != mPrimaryTextColor) && (mPrimaryDarkColor != mPrimaryTextColor);
  }
@Test
  public void isValidIfTextColorIsDifferentThanBackground() {
    Assert.assertTrue(overlay(Color.GRAY, Color.GRAY, Color.BLACK).isValid());
    Assert.assertTrue(overlay(Color.GRAY, Color.BLACK, Color.BLUE).isValid());
  }