testHighContrast() {
    const white = [255, 255, 255];
    const black = [0, 0, 0];
    const lemonchiffron = [255, 250, 205];
    const sienna = [160, 82, 45];

    const suggestion =
        googColor.highContrast(black, [white, black, sienna, lemonchiffron]);

    // should return an array of three numbers
    assertTrue('Return value is an array.', typeof suggestion == 'object');
    assertTrue('Return value is 3 long.', suggestion.length == 3);

    // known color combos should return a known (i.e. human-verified) suggestion
    assertArrayEquals(
        'White is best on sienna.',
        googColor.highContrast(sienna, [white, black, sienna, lemonchiffron]),
        white);
    assertArrayEquals(
        'Black is best on lemonchiffron.',
        googColor.highContrast(white, [white, black, sienna, lemonchiffron]),
        black);
  }
This method runs unit tests against googColor.highContrast().