public void isFalse() {
    if (actual == null) {
      isEqualTo(false); // fails
    } else if (actual) {
      failWithoutActual(simpleFact("expected to be false"));
    }
  }
@Test
  public void nullIsFalseFailing() {
    expectFailureWhenTestingThat(null).isFalse();
    assertFailureKeys("expected", "but was");
    assertFailureValue("expected", "false");
    assertFailureValue("but was", "null");
  }