LayoutTests/http/tests/paymentrequest/paymentmethodchange-couponCode.https.html

<!DOCTYPE html>
<meta charset="utf-8">
<title>Tests for `couponCode` being provided via `"paymentmethodchange"`.</title>
<script src="/js-test-resources/ui-helper.js"></script>
<script src="/resources/payment-request.js"></script>
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<body>
<script>
setup({ explicit_done: true, explicit_timeout: true });

user_activation_test(async (test) => {
    let request = new PaymentRequest([validPaymentMethod()], validPaymentDetails());
    request.addEventListener("merchantvalidation", (event) => {
        event.complete({ });
    });
    request.addEventListener("shippingaddresschange", (event) => {
        assert_equals(internals.mockPaymentCoordinator.couponCode, null, "check that the `couponCode` starts as `null`");
        event.updateWith({ });
        internals.mockPaymentCoordinator.changeCouponCode("TEST");
    });
    request.addEventListener("paymentmethodchange", (event) => {
        assert_equals(event.methodDetails.couponCode, "TEST", "check that `methodDetails` contains the `couponCode`");
        event.updateWith({ });
        internals.mockPaymentCoordinator.acceptPayment();
    });

    let response = await request.show();
    await response.complete("success");
}, "Should propagate `couponCode` if provided.");

done();
</script>