public void doesNotMatch(@Nullable String regex) {
    checkNotNull(regex);
    if (actual == null) {
      failWithActual("expected a string that does not match", regex);
    } else if (actual.matches(regex)) {
      failWithActual("expected not to match", regex);
    }
  }
@Test
  public void stringDoesNotMatchStringWithFail() {
    expectFailureWhenTestingThat("abcaaadev").doesNotMatch(".*aaa.*");
    assertFailureValue("expected not to match", ".*aaa.*");
  }