public async Task RemoveMessageFromUser()
        {
            var options = new DbContextOptionsBuilder <ApplicationDbContext>()
                          .UseInMemoryDatabase(databaseName: "RemoveMessageFromUser_Database")
                          .Options;
            var dbContext      = new ApplicationDbContext(options);
            var messageService = new MessageService(dbContext);

            await messageService.AddMessageToUserAsync("Message1", "u1", null);

            await messageService.AddMessageToUserAsync("Message2", "u2", null);

            await messageService.MakeAllMessagesOld("u1");

            await messageService.RemoveMessageFromUserAsync(1, "u1");

            var messagesCount = await dbContext.Messages.CountAsync();

            var message = await dbContext.Messages.FirstAsync();

            Assert.Equal(2, message.Id);
            Assert.Equal("Message2", message.Content);
            Assert.Equal("u2", message.UserId);
            Assert.True(message.IsNew);
            Assert.Equal(1, messagesCount);
        }