public void DeleteCourseByUId()
        {
            var options = new DbContextOptionsBuilder <ApplicationDbContext>()
                          .UseInMemoryDatabase(Guid.NewGuid().ToString());
            var repository     = new EfDeletableEntityRepository <Course>(new ApplicationDbContext(options.Options));
            var userRepository =
                new EfDeletableEntityRepository <ApplicationUser>(new ApplicationDbContext(options.Options));

            repository.AddAsync(new Course()
            {
                Title = "test", ApplicationUserId = "asd"
            }).GetAwaiter().GetResult();
            repository.SaveChangesAsync().GetAwaiter().GetResult();
            var coursesService = new CoursesService(repository, userRepository);

            AutoMapperConfig.RegisterMappings(typeof(MyTest).Assembly);
            var course = coursesService.DeleteAsync(1);

            Assert.Empty(repository.All());
        }