@Test
 public void shouldCalcFactorialForFour() {
   assertThat(fact.calc(4), is(24));
 }
 @Test
 public void shouldCalcFactorialForTen() {
   assertThat(fact.calc(10), is(3628800));
 }
 @Test
 public void shouldCalcFactorialForOne() {
   assertThat(fact.calc(1), is(1));
 }