@Test
public void testExpireKeySet() {

    JedisCluster mockJedisClient = mock(JedisCluster.class);
    CacheRedisClient mockedCachedRedisClient = mock(CacheRedisClient.class);
    when(mockedCachedRedisClient.getJedisClusterClient()).thenReturn(mockJedisClient);
    RedisCacheService redisCacheService = new RedisCacheService(config, mockedCachedRedisClient);
    Set<String> keys = new HashSet<>(Arrays.asList("key1", "key2"));
    redisCacheService.expire(keys, 10);
    verify(mockJedisClient, times(2)).expire(anyString(), anyInt());
}