public async Task AddCarrierShouldCreateNewCarrierIfItDoesntExist() { var options = new DbContextOptionsBuilder <WHMSDbContext>().UseInMemoryDatabase(databaseName: Guid.NewGuid().ToString()).Options; using var context = new WHMSDbContext(options); var mockInventoryService = new Mock <IInventoryService>(); var service = new ShippingService(context, mockInventoryService.Object); var carrierName = "FedEx"; await service.AddCarrierAsync(carrierName); var carrierDb = context.Carriers.FirstOrDefault(); Assert.NotNull(carrierDb); Assert.Equal(carrierName, carrierDb.Name); }