link-header-preload-non-html.html

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This test has a WPT meta file that expects 3 subtest issues.
This WPT test may be referenced by the following Test IDs:
- /preload/link-header-preload-non-html.html - WPT Dashboard Interop Dashboard

<!DOCTYPE html>

<meta charset=utf-8>

<title>Makes sure that Link headers preload resources in non-HTML documents</title>

<meta name="timeout" content="long">

<script src="resources/dummy.js?link-header-preload2"></script>

<script src="/common/utils.js"></script>

<script src="/resources/testharness.js"></script>

<script src="/resources/testharnessreport.js"></script>

<script src="/preload/resources/preload_helper.js"></script>

<body>

<script>

    function test_document_type(options, desc) {

        promise_test(async t => {

            const id = token();

            const preloadLink = `/html/semantics/document-metadata/the-link-element/stylesheet.py?id=${id}`;

            const params = new URLSearchParams();

            for (const opt in options)

                params.set(opt, options[opt]);

            params.set('link', `<${preloadLink}>;rel=preload;as=style`);

            const docURL = getAbsoluteURL(`./resources/echo-preload-header.py?${params.toString()}`);

            const iframe = document.createElement('iframe');

            t.add_cleanup(() => iframe.remove());

            iframe.src = docURL;

            document.body.appendChild(iframe);

            await new Promise(resolve => iframe.addEventListener('load', resolve));

            const timeout = 5000;

            const interval = 25;

            let count = 0;

            const before = performance.now();

            while (performance.now() < before + timeout) {

                // count=true returns the number of times the resource was accessed

                const res = await fetch(preloadLink + '&count=true');

                // If count is positive, the resource was accessed.

                count = Number(await res.text());

                if (count > 0)

                    break;

                await new Promise(resolve => t.step_timeout(resolve, interval));

            assert_equals(count, 1, "verify that request was issued exactly once");

        }, `${desc} documents should respect preload Link headers`);

    test_document_type({

        type: 'application/xml',

        content: `<?xml version="1.0" encoding="utf-8"?>

        <html xmlns="http://www.w3.org/1999/xhtml">

        </html>`}, "XHTML");

    test_document_type({content: 'Hello', type: 'text/plain'}, 'plain text');

    test_document_type({file: 'square.png', type: 'image/png'}, 'image');

    test_document_type({file: 'white.mp4', type: 'video/mp4'}, 'media');

    test_document_type({content: 'dummy', type: 'image/png'}, 'invalid image');

</script>

</body>