NewsBrowserViewModel model = new NewsBrowserViewModel(null);
model.setInput(elements, 5);
assertTrue(model.isFirstItemUnread());
assertEquals(-1L, model.findGroup(5L));
assertEquals(-1L, model.getExpandedNews());
model.setNewsExpanded(news3, true);
assertEquals(3L, model.getExpandedNews());
assertTrue(model.getGroups().isEmpty());
assertEquals(0, model.getGroupSize(5L));