@Test
  public void containsIntegersWithinRange() {
    Range range = new Range(1, 3);

    assertThat(range.contains(1)).isTrue();
    assertThat(range.contains(2)).isTrue();
    assertThat(range.contains(3)).isTrue();
    assertThat(range.contains(4)).isFalse();
  }
  @Test
  public void failure() {
    Range range = new Range(1, 3);

    assertThat(range.contains(4)).isTrue();
  }