### Question:
RedisClient implements Client { @Override public int dbsize() throws ConnectionException, IOException { transaction.open(); try { commandExecutor.execute(RedisCommands.DBSIZE); return commandResult.getInt(); } finally { transaction.close(); } } RedisClient(final RedisCommandExecutor redisCommandExecutor,
      final RedisCommandResult redisCommandResult);  RedisClient(final Connection connection);  RedisClient();  RedisClient(final String host);  RedisClient(final String host, final int port); @Override void ping(); @Override void set(final byte[] key, final byte[] value); @Override void set(final byte[] key, final byte[] value, final long expiryInMillis); byte[] longToBytes(final long longToBeConverted); @Override byte[] get(final byte[] key); @Override byte[] expire(final byte[] key); @Override void flushdb(); @Override int dbsize();  }### Answer:
@Test public void dbsize() throws ConnectionException, IOException { int size = 3; doReturn(size).when(commandResult).getInt(); int actualSize = redisClient.dbsize(); verify(commandExecutor).execute(RedisCommands.DBSIZE); assertEquals(size, actualSize); }