public StringSubject factValue(String key) {
    return doFactValue(key, null);
  }
@Test
  public void factValueIntFailWrongValue() {
    expectFailureWhenTestingThat(fact("foo", "the foo")).factValue("foo", 0).isEqualTo("the bar");
    assertFailureValue("value of", "failure.factValue(foo, 0)");
  }