public async Task <bool> AddAllEntitiesAsync()
        {
            // create new Department
            var departMentName = $"department_{Guid.NewGuid():N}";
            var department     = _departmentRepository.AddDepartment(departMentName);

            // create new User with above Department
            var userName  = $"user_{Guid.NewGuid():N}";
            var userEmail = $"{Guid.NewGuid():N}@gmail.com";
            var user      = _userRepository.NewUser(userName, userEmail, department);

            // create new Salary with above User
            float coefficientsSalary = new Random().Next(1, 15);
            float workdays           = 22;
            var   salary             = _salaryRepository.AddUserSalary(user, coefficientsSalary, workdays);

            // Commit all changes with one single commit
            var saved = await _unitOfWork.CommitAsync();

            return(saved > 0);
        }