@Test(expected = PreprocessingException.class)
public void executeTest_equalWidth_diffHeight() {

    BufferedImage img1 = BufferedImageHelper.createSolidImage(new Color(0, 0, 0), 500, 500);
    BufferedImage img2 = BufferedImageHelper.createSolidImage(new Color(0, 0, 0), 500, 200);
    CheckEqualSizePreprocessor pp = new CheckEqualSizePreprocessor(img1, img2);
    pp.process();
}