compute_pressure_rate_obfuscation_mitigation_triggered.https.window.js

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This test has a WPT meta file that expects 1 subtest issues.
This WPT test may be referenced by the following Test IDs:
- /compute-pressure/compute_pressure_rate_obfuscation_mitigation_triggered.https.window.html - WPT Dashboard Interop Dashboard

// META: timeout=long

// META: script=/resources/test-only-api.js

// META: script=resources/pressure-helpers.js

// META: global=window,dedicatedworker,sharedworker

'use strict';

pressure_test(async (t, mockPressureService) => {

  const sampleIntervalInMs = 40;

  const readings = ['nominal', 'fair', 'serious', 'critical'];

  // Normative values for rate obfuscation parameters.

  // https://w3c.github.io/compute-pressure/#rate-obfuscation-normative-parameters.

  const minPenaltyTimeInMs = 5000;

  const maxChangesThreshold = 100;

  const minChangesThreshold = 50;

  let gotPenalty = false;

  await new Promise(async resolve => {

    const observerChanges = [];

    const observer = new PressureObserver(changes => {

      if (observerChanges.length >= (minChangesThreshold - 1)) {

        const lastSample = observerChanges.at(-1);

        if ((changes[0].time - lastSample[0].time) >= minPenaltyTimeInMs) {

          // The update delivery might still be working even if

          // maxChangesThreshold have been reached and before disconnect() is

          // processed.

          // Therefore we are adding a flag to dismiss any updates after the

          // penalty is detected, which is the condition for the test to pass.

          gotPenalty = true;

          observer.disconnect();

          resolve();

      observerChanges.push(changes);

});

    observer.observe('cpu', {sampleInterval: sampleIntervalInMs});

    mockPressureService.startPlatformCollector(sampleIntervalInMs);

    let i = 0;

    // mockPressureService.updatesDelivered() does not necessarily match

    // pressureChanges.length, as system load and browser optimizations can

    // cause the actual timer used by mockPressureService to deliver readings

    // to be a bit slower or faster than requested.

    while (observerChanges.length <= maxChangesThreshold || !gotPenalty) {

      mockPressureService.setPressureUpdate(

          'cpu', readings[i++ % readings.length]);

      // Allow tasks to run (avoid a micro-task loop).

      await new Promise((resolve) => t.step_timeout(resolve, 0));

      await t.step_wait(

          () => mockPressureService.updatesDelivered() >= i,

          `At least ${i} readings have been delivered`);

    assert_true(gotPenalty, 'Penalty not triggered');

});

}, 'Rate obfuscation mitigation should have been triggered, when changes is higher than minimum changes before penalty');