@Test public void shouldNotModifyIfStartPaintingInOnePixelWithTheColorToPaint() {

  int[][] picture = {
      { 1, 1, 1, 1 }, { 1, 0, 0, 1 }, { 1, 0, 0, 1 }, { 1, 1, 1, 1 }
  };
  int colorToReplace = 0;
  int colorToPaint = 1;
  int x = 0;
  int y = 0;
  floodFill.apply(picture, colorToReplace, colorToPaint, x, y);
  int[][] expectedResult = {
      { 1, 1, 1, 1 }, { 1, 0, 0, 1 }, { 1, 0, 0, 1 }, { 1, 1, 1, 1 }
  };
  assertArrayEquals(expectedResult, picture);
}