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

    return Optional.ofNullable(rulesByUuid.get(uuid));
  }
@Test
  public void first_call_to_findById_triggers_call_to_db_and_any_subsequent_get_or_find_call_does_not() {
    underTest.findByUuid(AB_RULE.getUuid());

    verify(ruleDao, times(1)).selectAll(any(DbSession.class));

    verifyNoMethodCallTriggersCallToDB();
  }