@Test
public void shouldFilterByIsNull() {

	DummyModel model = createModel("column1", "column2");
	DummyModel model1 = createModel("column1", null);
	Filter filter = new Filter(new Condition("column2", Operator.is_null));
	List<DummyModel> models = DummyModel.where(filter);
	assertEquals(models.size(), 1);
	assertEquals(models.get(0), model1);
}