@Test
 public void shouldReturnFalse() {
   NaturalNums nn = new NaturalNums();
   assertEquals(false, nn.isItDivisible(11));
 }
 @Test
 public void shouldFindAllNumsDivisibleByThreeOrFiveUnderTen() {
   NaturalNums nn = new NaturalNums();
   assertEquals(3 + 5 + 6 + 9, nn.run(10));
 }
 @Test
 public void shouldReturnZero() {
   NaturalNums nn = new NaturalNums();
   assertEquals(0, nn.run(1));
 }
 @Test
 public void shouldReturnTrue() {
   NaturalNums nn = new NaturalNums();
   assertEquals(true, nn.isItDivisible(36));
 }