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);
}
