performance-speculations-used-preload.tentative.html

Enable keyboard shortcuts

This test has a WPT meta file that expects 8 subtest issues.
This WPT test may be referenced by the following Test IDs:
- /speculation-rules/speculation-measurement/performance-speculations-used-preload.tentative.html - WPT Dashboard Interop Dashboard

<!DOCTYPE html>

<meta charset="utf-8">

<title>performance.getSpeculations() - used preloads with various as/crossorigin</title>

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

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

<script src="support/speculation-measurement-utils.js"></script>

<body>

<script>

// Test matrix: combinations of "as" and "crossorigin" for used preloads.

// Note: as=fetch without crossorigin is excluded because <link rel=preload

// as=fetch> (no-cors mode) does not match fetch() (cors mode by default).

// The crossorigin attribute must match between preload and consumption.

const testCases = [

  {as: 'script', crossorigin: null},

  {as: 'script', crossorigin: 'anonymous'},

  {as: 'script', crossorigin: 'use-credentials'},

  {as: 'style',  crossorigin: null},

  {as: 'style',  crossorigin: 'anonymous'},

  {as: 'style',  crossorigin: 'use-credentials'},

  {as: 'fetch',  crossorigin: 'anonymous'},

  {as: 'fetch',  crossorigin: 'use-credentials'},

];

for (const {as, crossorigin} of testCases) {

  const coLabel = crossorigin === null ? 'no crossorigin' :

                                         `crossorigin=${crossorigin}`;

  promise_test(async t => {

    assert_true(isSpeculationMeasurementEnabled(),

      "SpeculationMeasurement feature must be enabled");

    const tag = `${as}-${crossorigin}-used`;

    const href = supportFileUrl(as, tag);

    const beforePreload = performance.now();

    await addPreloadAndWait({t, as, crossorigin, href});

    // Before use: preload should be tracked but unused.

    let preload = findPreloadByUrl(performance.getSpeculations().preloads, tag);

    assert_not_equals(preload, undefined, "preload entry should exist");

    assert_equals(preload.used, null,

      "preload should be unused before consumption");

    // Consume the preloaded resource.

    await usePreload({t, as, href, crossorigin});

    const afterUse = performance.now();

    // After use: preload should have a timestamp.

    preload = findPreloadByUrl(performance.getSpeculations().preloads, tag);

    assert_not_equals(preload, undefined,

      "preload entry should still exist after use");

    assert_equals(preload.as, as, `as should be '${as}'`);

    assert_equals(preload.crossorigin, expectedCrossOriginMode(crossorigin),

      `crossorigin should be '${expectedCrossOriginMode(crossorigin)}'`);

    assert_not_equals(preload.used, null,

      "used preload should have a timestamp, not null");

    assert_equals(typeof preload.used, "number",

      "used should be a DOMHighResTimeStamp (number)");

    assert_greater_than_equal(preload.used, beforePreload,

      "used timestamp should be >= beforePreload");

    assert_less_than_equal(preload.used, afterUse,

      "used timestamp should be <= afterUse");

  }, `Used preload: as=${as}, ${coLabel}`);

</script>

</body>