public async Task AddEmployeeAsyncShouldWorkCorrectly()
        {
            var options = new DbContextOptionsBuilder <ApplicationDbContext>()
                          .UseInMemoryDatabase(databaseName: Guid.NewGuid().ToString()).Options;
            var dbContext = new ApplicationDbContext(options);

            var teamRepo     = new EfDeletableEntityRepository <Team>(dbContext);
            var employeeRepo = new EfDeletableEntityRepository <ApplicationUser>(dbContext);

            var service = new TeamService(teamRepo, employeeRepo);

            var employeeId = Guid.NewGuid().ToString();
            var teamId     = 1;

            await teamRepo.AddAsync(new Team());

            await teamRepo.SaveChangesAsync();

            await employeeRepo.AddAsync(new ApplicationUser
            {
                Id = employeeId,
            });

            await employeeRepo.SaveChangesAsync();

            await service.AddEmployeeAsync(teamId, employeeId);

            var team = await teamRepo.All()
                       .FirstOrDefaultAsync();

            var employee = await employeeRepo.All()
                           .FirstOrDefaultAsync();

            Assert.Contains(team.Employees, x => x.Id == employeeId);
            Assert.Equal(teamId, team.Id);
        }