JCF를 이용한 집합 연산 단위 테스트

public class SetTest3 {

	private static final Integer[] UNION = {1, 2, 3, 4, 5};
	private static final Integer[] INTERSECTION = {3};
	private static final Integer[] DIFFERENCES = {1, 2};

	private Set<Integer> a;
	private List<Integer> b;
	
	@Before
	public void setUp(){
		a = new HashSet<Integer>(Arrays.asList(1, 2, 3));
		b = Arrays.asList(3, 4, 5);		
	}
	
	@Test
	public void test_합집합() {
		a.addAll(b);
		assertArrayEquals(UNION, a.toArray());
	}
	
	@Test
	public void test_차집합(){
		a.removeAll(b);
		assertArrayEquals(DIFFERENCES, a.toArray());
	}
	
	@Test
	public void test_교집합(){
		a.retainAll(b);
		assertArrayEquals(INTERSECTION, a.toArray());
	}

}