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

            var repository = new EfDeletableEntityRepository <VehicleCategory>(dbContext);
            var service    = new VehicleCategoriesService(repository);

            Assert.Empty(service.GetAll <VehicleCategory>());

            await service.AddAsync("Sedan");

            Assert.Single(service.GetAll <VehicleCategory>());
        }
        public async Task GetAllGenericShouldWork()
        {
            var options = new DbContextOptionsBuilder <ApplicationDbContext>()
                          .UseInMemoryDatabase(databaseName: "GetAllGenericShouldWork").Options;
            var dbContext = new ApplicationDbContext(options);

            dbContext.VehicleCategories.Add(new VehicleCategory());
            dbContext.VehicleCategories.Add(new VehicleCategory());
            dbContext.VehicleCategories.Add(new VehicleCategory());
            await dbContext.SaveChangesAsync();

            var repository = new EfDeletableEntityRepository <VehicleCategory>(dbContext);
            var service    = new VehicleCategoriesService(repository);

            Assert.Equal(3, service.GetAll <VehicleCategory>().Count());
        }