public async Task Add_RentalCreated() { var context = MockLibrarySystemContext(); var repository = new RentalsRepository(context.Object); var rental = new Rental { }; await repository.Add(rental); context.Verify(context => context.Add(rental), Times.AtLeastOnce); context.Verify(context => context.SaveChangesAsync(It.IsAny <CancellationToken>()), Times.AtLeastOnce); }