1 files changed, 150 insertions, 0 deletions
diff --git a/dom/media/mediacontrol/tests/browser/browser_media_control_position_state.js b/dom/media/mediacontrol/tests/browser/browser_media_control_position_state.js
new file mode 100644
index 0000000000..f32ce26063
--- /dev/null
+++ b/dom/media/mediacontrol/tests/browser/browser_media_control_position_state.js
@@ -0,0 +1,150 @@
+const PAGE_URL =
+  "https://example.com/browser/dom/media/mediacontrol/tests/browser/file_non_autoplay.html";
+const IFRAME_URL =
+  "https://example.com/browser/dom/media/mediacontrol/tests/browser/file_iframe_media.html";
+
+const testVideoId = "video";
+
+add_task(async function setupTestingPref() {
+  await SpecialPowers.pushPrefEnv({
+    set: [
+      ["media.mediacontrol.testingevents.enabled", true],
+      ["dom.media.mediasession.enabled", true],
+    ],
+  });
+});
+
+/**
+ * This test is used to check if we can receive correct position state change,
+ * when we set the position state to the media session.
+ */
+add_task(async function testSetPositionState() {
+  info(`open media page`);
+  const tab = await createLoadedTabWrapper(PAGE_URL);
+
+  info(`start media`);
+  await playMedia(tab, testVideoId);
+
+  info(`set duration only`);
+  await setPositionState(tab, {
+    duration: 60,
+  });
+
+  info(`set duration and playback rate`);
+  await setPositionState(tab, {
+    duration: 50,
+    playbackRate: 2.0,
+  });
+
+  info(`set duration, playback rate and position`);
+  await setPositionState(tab, {
+    duration: 40,
+    playbackRate: 3.0,
+    position: 10,
+  });
+
+  info(`remove tab`);
+  await tab.close();
+});
+
+add_task(async function testSetPositionStateFromInactiveMediaSession() {
+  info(`open media page`);
+  const tab = await createLoadedTabWrapper(PAGE_URL);
+
+  info(`start media`);
+  await playMedia(tab, testVideoId);
+
+  info(
+    `add an event listener to measure how many times the position state changes`
+  );
+  let positionChangedNum = 0;
+  const controller = tab.linkedBrowser.browsingContext.mediaController;
+  controller.onpositionstatechange = () => positionChangedNum++;
+
+  info(`set position state on the main page which has an active media session`);
+  await setPositionState(tab, {
+    duration: 60,
+  });
+
+  info(`set position state on the iframe which has an inactive media session`);
+  await setPositionStateOnInactiveMediaSession(tab);
+
+  info(`set position state on the main page again`);
+  await setPositionState(tab, {
+    duration: 60,
+  });
+  is(
+    positionChangedNum,
+    2,
+    `We should only receive two times of position change, because ` +
+      `the second one which performs on inactive media session is effectless`
+  );
+
+  info(`remove tab`);
+  await tab.close();
+});
+
+/**
+ * The following are helper functions.
+ */
+async function setPositionState(tab, positionState) {
+  const controller = tab.linkedBrowser.browsingContext.mediaController;
+  const positionStateChanged = new Promise(r => {
+    controller.addEventListener(
+      "positionstatechange",
+      event => {
+        const { duration, playbackRate, position } = positionState;
+        // duration is mandatory.
+        is(
+          event.duration,
+          duration,
+          `expected duration ${event.duration} is equal to ${duration}`
+        );
+
+        // Playback rate is optional, if it's not present, default should be 1.0
+        if (playbackRate) {
+          is(
+            event.playbackRate,
+            playbackRate,
+            `expected playbackRate ${event.playbackRate} is equal to ${playbackRate}`
+          );
+        } else {
+          is(event.playbackRate, 1.0, `expected default playbackRate is 1.0`);
+        }
+
+        // Position state is optional, if it's not present, default should be 0.0
+        if (position) {
+          is(
+            event.position,
+            position,
+            `expected position ${event.position} is equal to ${position}`
+          );
+        } else {
+          is(event.position, 0.0, `expected default position is 0.0`);
+        }
+        r();
+      },
+      { once: true }
+    );
+  });
+  await SpecialPowers.spawn(
+    tab.linkedBrowser,
+    [positionState],
+    positionState => {
+      content.navigator.mediaSession.setPositionState(positionState);
+    }
+  );
+  await positionStateChanged;
+}
+
+async function setPositionStateOnInactiveMediaSession(tab) {
+  return SpecialPowers.spawn(tab.linkedBrowser, [IFRAME_URL], async url => {
+    info(`create iframe and wait until it finishes loading`);
+    const iframe = content.document.getElementById("iframe");
+    iframe.src = url;
+    await new Promise(r => (iframe.onload = r));
+
+    info(`trigger media in iframe entering into fullscreen`);
+    iframe.contentWindow.postMessage("setPositionState", "*");
+  });
+}