public StringSubject factValue(String key) {
    return doFactValue(key, null);
  }
@Test
  public void factValueIntFailNotEnoughWithKey() {
    Object unused = expectFailureWhenTestingThat(fact("foo", "the foo")).factValue("foo", 5);
    assertFailureKeys("for key", "index too high", "fact count was");
    assertFailureValue("for key", "foo");
    assertFailureValue("index too high", "5");
    assertFailureValue("fact count was", "1");
  }