public <T extends ShardingSphereRule> Optional<T> findSingleRule(final Class<T> clazz) {
        Collection<T> foundRules = findRules(clazz);
        return foundRules.isEmpty() ? Optional.empty() : Optional.of(foundRules.iterator().next());
    }
@Test
    void assertFindSingleRule() {
        assertTrue(ruleMetaData.findSingleRule(ShardingSphereRuleFixture.class).isPresent());
    }