@Override
  public Optional<Rule> findByKey(RuleKey key) {
    verifyKeyArgument(key);

    ensureInitialized();

    return Optional.ofNullable(rulesByKey.get(key));
  }
@Test
  public void findByKey_returns_Rule_if_argument_is_deprecated_key_in_DB_of_rule_in_DB() {
    Optional<Rule> rule = underTest.findByKey(AB_RULE_DEPRECATED_KEY_1);

    assertIsABRule(rule.get());
  }