public void isNotEmpty() {
    if (actual == null) {
      failWithActual(simpleFact("expected a non-empty string"));
    } else if (actual.isEmpty()) {
      failWithoutActual(simpleFact("expected not to be empty"));
    }
  }
@Test
  public void stringIsNotEmptyFail() {
    expectFailureWhenTestingThat("").isNotEmpty();
    assertFailureKeys("expected not to be empty");
  }