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  <script type="application/javascript" src="mediaStreamPlayback.js"></script>
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<pre id="test">
<script type="application/javascript">
createHTML({
  title: "getUserMedia multiple times, concurrently, and with different constraints",
  bug: "1404977"
});
/**
  * Verify that we can successfully call getUserMedia multiple times for the
  * same device, concurrently. This is checked by calling getUserMedia a number
  * of times with different constraints. We verify that the stream returned by
  * that call has the same constraints as requested both immediately after the
  * call and after all gUM calls have been made. The test then verifies the
  * streams can be played.
  */
runTest(async function() {
  // Compare constraints and return a string with the differences in
  // echoCancellation, autoGainControl, and noiseSuppression. The string
  // will be empty if there are no differences.
  function getConstraintDifferenceString(constraints, otherConstraints) {
    let diffString = "";
    if (constraints.echoCancellation != otherConstraints.echoCancellation) {
      diffString += "echoCancellation different: " +
                    `${constraints.echoCancellation} != ${otherConstraints.echoCancellation}, `;
    }
    if (constraints.autoGainControl != otherConstraints.autoGainControl) {
      diffString += "autoGainControl different: " +
                    `${constraints.autoGainControl} != ${otherConstraints.autoGainControl}, `;
    }
    if (constraints.noiseSuppression != otherConstraints.noiseSuppression) {
      diffString += "noiseSuppression different: " +
                    `${constraints.noiseSuppression} != ${otherConstraints.noiseSuppression}, `;
    }
    // Replace trailing comma and space if any
    return diffString.replace(/, $/, "");
  }

  // We need a real device to get a MediaEngine supporting constraints
  let audioDevice = SpecialPowers.getCharPref("media.audio_loopback_dev", "");
  if (!audioDevice) {
    todo(false, "No device set by framework. Try --use-test-media-devices");
    return;
  }

  let egn = (e, g, n) => ({
    echoCancellation: e,
    autoGainControl: g,
    noiseSuppression: n
  });

  let constraintCombinations = [
    egn(false, false, false),
    egn(true,  false, false),
    egn(false, true,  false),
    egn(false, false, true),
    egn(true,  true,  false),
    egn(true,  false, true),
    egn(false, true,  true),
    egn(true,  true,  true),
  ];

  // Array to store objects that associate information used in our test such as
  // constraints, gum streams, and various promises.
  let testCases = [];

  for (let constraints of constraintCombinations) {
    let testCase = {requestedConstraints: constraints};
    // Provide an id for logging, labeling related elements.
    testCase.id = `testCase.` +
                  `e=${constraints.echoCancellation}.` +
                  `g=${constraints.noiseSuppression}.` +
                  `n=${constraints.noiseSuppression}`;
    testCases.push(testCase);
    testCase.gumStream =
      await getUserMedia({audio: testCase.requestedConstraints})
      .catch(e => Promise.reject(`getUserMedia calls should not fail! Failed at ${testCase.id} with: ${e}!`));
    let differenceString = getConstraintDifferenceString(
      testCase.requestedConstraints,
      testCase.gumStream.getAudioTracks()[0].getSettings());
      ok(!differenceString,
        `gUM stream for ${testCase.id} should have the same constraints as were ` +
        `requested from gUM. Differences: ${differenceString}`);
  }
  is(testCases.length,
    constraintCombinations.length,
    "Should have a stream for each constraint");

  // Once all streams are collected, make sure the constraints haven't been
  // mutated by another gUM call.
  for (let testCase of testCases) {
    let differenceString = getConstraintDifferenceString(
      testCase.requestedConstraints,
      testCase.gumStream.getAudioTracks()[0].getSettings());
    ok(!differenceString,
      `gUM stream for ${testCase.id} should not have had constraints altered after ` +
      `all gUM calls are done. Differences: ${differenceString}`);
  }

  // We do not currently have tests to verify the behaviour of the different
  // constraints. Once we do we should do further verificaiton here. See
  // bug 1406372, bug 1406376, and bug 1406377.

  for (let testCase of testCases) {
    let testAudio = createMediaElement("audio", `testAudio.${testCase.id}`);
    let playback = new MediaStreamPlayback(testAudio, testCase.gumStream);
    await playback.playMediaWithoutStoppingTracks(false);
  }

  // Stop the tracks for each stream, we left them running above via
  // playMediaWithoutStoppingTracks to make sure they can play concurrently.
  for (let testCase of testCases) {
    testCase.gumStream.getTracks().map(t => t.stop());
  }
});
</script>
</pre>
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