@Test
public void shouldGiveAllPrimeNumbersBetween7And31_sieve() throws Exception {

    List<Integer> primeNumbers = P34.primeNumbers_sieve(7, 31);
    assertThat(primeNumbers, hasSize(8));
    assertThat(primeNumbers, hasItems(7, 11, 13, 17, 19, 23, 29, 31));
}