	@Test
	public void testFindMostPopular() {

		Integer[] array = {1, 2, 2, 3, 4, 5, 5, 5, 6, 7, 7, 8};
		List<Integer> list = new ArrayList<>(Arrays.asList(array));

		assertEquals((Integer) 5, CollectionUtils.findMostPopularElement(list));
	}