public async Task GetInvoiceItemsTest() { // Arrange var filter = new InvoiceItemListFilter(); _stripe.Get( Arg.Is <StripeRequest <InvoiceItemListFilter, Pagination <InvoiceItem> > >( a => a.UrlPath == "invoiceitems" && a.Model == filter), _cancellationToken) .Returns(Task.FromResult(new StripeResponse <Pagination <InvoiceItem> >())); // Act var response = await _client.GetInvoiceItems(filter, _cancellationToken); // Assert response.Should().NotBeNull(); }