public void testGetTrainDescriptors() {
    Mat train = new Mat(1, 1, CvType.CV_8U, new Scalar(123));
    Mat truth = train.clone();
    matcher.add(Arrays.asList(train));

    List<Mat> descriptors = matcher.getTrainDescriptors();

    assertEquals(1, descriptors.size());
    assertMatEqual(truth, descriptors.get(0));
  }