LayoutTests/http/tests/printing/print-from-load-handler.html

<!DOCTYPE html>
<html>
<head>
<script src="/js-test-resources/js-test.js"></script>
</head>
<body>
<script>
description("window.print() called from the load event handler prints once the load event is done, even when nothing is loading.");
jsTestIsAsync = true;

// The load event waits for the iframe. When the iframe finishes, this document has nothing left loading.
document.write(`<iframe src="/resources/load-and-stall.py?name=dummy.js&mimeType=text%2Fplain&stallAt=0&stallFor=0.3&rand=${Math.random()}"></iframe>`);

let loadHandlerReturned = false;
let loadHandlerReturnedBeforePrint;

addEventListener("beforeprint", () => {
    loadHandlerReturnedBeforePrint = loadHandlerReturned;
});

addEventListener("afterprint", () => {
    shouldBeTrue("loadHandlerReturnedBeforePrint");
    finishJSTest();
});

onload = () => {
    evalAndLog("window.print()");
    loadHandlerReturned = true;
};
</script>
</body>
</html>