@Test
 public void itShouldReturn256() throws Exception {
   assertThat(
       primeFactory.computePrimeDivisors(256),
       is(
           new Integer[] {
             2, 2, 2, 2, 2, 2, 2, 2,
           }));
 }
 @Test
 public void fourShouldBePrime() throws Exception {
   assertFalse(primeFactory.isPrime(4));
 }
 @Test
 public void threeShouldBePrime() throws Exception {
   assertTrue(primeFactory.isPrime(3));
 }