public void ShouldChangeChatPicture() { //arrange var user = new User { Name = "testCharUser", Picture = new byte[] { } }; var login = "******"; var password = "******"; var title = "chatTitle"; var pic = new byte[] { }; var newPic = 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); chatRepository.ChangePicture(resultChat.Id, newPic); resultChat = chatRepository.Get(resultChat.Id); //asserts Assert.AreEqual(newPic, resultChat.Picture); }