testColorBlend() {
    // Define some RGB colors for our tests.
    const black = [0, 0, 0];
    const blue = [0, 0, 255];
    const gray = [128, 128, 128];
    const green = [0, 255, 0];
    const purple = [128, 0, 128];
    const red = [255, 0, 0];
    const yellow = [255, 255, 0];
    const white = [255, 255, 255];

    // Blend arbitrary colors, using 0 and 1 for factors. Using 0 should return
    // the first color, while using 1 should return the second color.
    const redWithNoGreen = googColor.blend(red, green, 1);
    assertTrue('red + 0 * green = red', rgbColorsAreEqual(red, redWithNoGreen));
    const whiteWithAllBlue = googColor.blend(white, blue, 0);
    assertTrue(
        'white + 1 * blue = blue', rgbColorsAreEqual(blue, whiteWithAllBlue));

    // Blend the same colors using arbitrary factors. This should return the
    // same colors.
    const greenWithGreen = googColor.blend(green, green, .25);
    assertTrue(
        'green + .25 * green = green',
        rgbColorsAreEqual(green, greenWithGreen));

    // Blend different colors using varying factors.
    const blackWithWhite = googColor.blend(black, white, .5);
    assertTrue(
        'black + .5 * white = gray', rgbColorsAreEqual(gray, blackWithWhite));
    const redAndBlue = googColor.blend(red, blue, .5);
    assertTrue(
        'red + .5 * blue = purple', rgbColorsAreEqual(purple, redAndBlue));
    const lightGreen = googColor.blend(green, white, .75);
    assertTrue(
        'green + .25 * white = a lighter shade of white',
        lightGreen[0] > 0 && lightGreen[1] == 255 && lightGreen[2] > 0);

    // Blend arbitrary colors using factors outside the expected range.
    const noGreenAllPurple = googColor.blend(green, purple, -0.5);
    assertTrue(
        'green * -0.5 + purple = purple.',
        rgbColorsAreEqual(purple, noGreenAllPurple));
    const allBlueNoYellow = googColor.blend(blue, yellow, 1.37);
    assertTrue(
        'blue * 1.37 + yellow = blue.',
        rgbColorsAreEqual(blue, allBlueNoYellow));
  }
This method runs unit tests against googColor.blend().  Test cases include:
blending arbitrary colors with factors of 0 and 1, blending the same colors
using arbitrary factors, blending different colors of varying factors,
and blending colors using factors outside the expected range.