svoid checkPixelArray(int[] pixels, int... expected) {
  assertEquals(l(pixels), l(expected);
  for i over pixels:
    if (pixels[i] != expected[i])
      fail("pixel " + i + ": " + intToHex(pixels[i]) + " vs " + intToHex(expected[i]));
}

svoid checkPixelArray(BufferedImage img, int... expectedPixels) {
  int[] pixels = grabbableIntPixels_fastOrSlow(img).asPackedArray();
  checkPixelArray(pixels, expectedPixels);
}

Began life as a copy of #1033286