<!doctype html>
<script src=/resources/testharness.js></script>
<script src=/resources/testharnessreport.js></script>
<script>
promise_test(t => {
return new Promise(resolve => {
window.addEventListener("DOMContentLoaded", resolve);
});
}, "Wait for the DOM to be built.");
promise_test(async t => {
let iframe = document.createElement("iframe");
let iframe_loaded = new Promise(resolve => iframe.onload = resolve);
iframe.src = "about:blank";
document.body.appendChild(iframe);
// The about:blank document can load.
await iframe_loaded;
assert_not_equals(iframe.contentDocument, null);
}, "about:blank can always be embedded by a 'require-corp' document");
promise_test(async t => {
let iframe_C = document.createElement("iframe");
let iframe_B = document.createElement("iframe");
iframe_B.src = "about:blank";
iframe_C.src = "/common/blank.html";
let iframe_B_loaded = new Promise(resolve => iframe_B.onload = resolve);
document.body.appendChild(iframe_B);
// The about:blank frame must be able to load.
await iframe_B_loaded;
assert_not_equals(iframe_B.contentDocument, null);
iframe_B.contentDocument.body.appendChild(iframe_C);
// The document nested under about:blank must not load because it does not
// specify the Cross-Origin-Embedder-Policy: require-corp header.
// An error page must be displayed instead.
// See https://github.com/whatwg/html/issues/125 for why a timeout is used
// here. Long term all network error handling should be similar and have a
// reliable event.
assert_equals(iframe_C.contentWindow.location.href, "about:blank");
assert_not_equals(iframe_C.contentDocument, null);
await t.step_wait(() => iframe_C.contentDocument === null);
}, "A(B(C)) A=require-corp, B=about:blank, C=no-require-corp => C can't load");
</script>