public static void assertNullTransformation(
      Transformations<Transformation> transformations, String name) {

    assertEquals(
        "the null Transformation should be returned for the name " + name,
        NULL_TRANSFORMATION,
        transformations.get(name));
  }
  public static void assertNullTransformation(
      Transformations<Transformation> transformations, int index) {

    assertEquals(
        "the null Transformation should be returned for the index " + index,
        NULL_TRANSFORMATION,
        transformations.get(index));
  }