public void ShouldCheckExistanceOfChat()
        {
            //arrange
            var user = new User
            {
                Name    = "testCharUser",
                Picture = new byte[] { }
            };
            var login    = "******";
            var password = "******";
            var title    = "chatTitle";
            var pic      = new byte[] {};

            //act
            var userRepository = new UsersRepository(ConnectionString);
            var resultUser1    = userRepository.Create(user, login, password);
            var resultUser2    = userRepository.Create(user, login + "1", password);
            var userIds        = new List <Guid> {
                resultUser1.Id, resultUser2.Id
            };

            _tempUsers.AddRange(userIds);
            var chatRepository = new ChatsRepository(ConnectionString);
            var resultChat     = chatRepository.Create(title, userIds, pic);

            _tempChats.Add(resultChat.Id);

            //asserts
            Assert.AreEqual(chatRepository.ChatExists(resultChat.Id), true);
            Assert.AreEqual(chatRepository.ChatExists(Guid.Empty), false);
        }