@Test
	public void addTest() {
		for (int i = 0; i < TESTS; i++) {
			double x1 = rand.nextInt();
			double y1 = rand.nextInt();
			double x2 = rand.nextInt();
			double y2 = rand.nextInt();
			Vector v1 = new Vector(x1, y1);
			Vector v2 = new Vector(x2, y2);
			Vector res = new Vector(x1 + x2, y1 + y2);
			assertEquals(res, v1.add(v2));
		}
	}