@Override
  public Optional<Rule> findByUuid(String uuid) {
    ensureInitialized();

    return Optional.ofNullable(rulesByUuid.get(uuid));
  }
@Test
  public void findByUuid_returns_Rule_if_it_exists_in_DB() {
    Optional<Rule> rule = underTest.findByUuid(AB_RULE.getUuid());

    assertIsABRule(rule.get());
  }