@Test
public void testNullParamFails() {

    expectedEx.expect(IllegalArgumentException.class);
    expectedEx.expectMessage("params can't be null");
    HoltWintersSimpleTrainingModel subject = new HoltWintersSimpleTrainingModel(HoltWintersAustouristsTestHelper.buildAustouristsParams(HoltWintersSeasonalityType.MULTIPLICATIVE));
    subject.observeAndTrain(0, null, null);
}