1 files changed, 201 insertions, 0 deletions
diff --git a/dom/media/mediasession/test/browser_active_mediasession_among_tabs.js b/dom/media/mediasession/test/browser_active_mediasession_among_tabs.js
new file mode 100644
index 0000000000..a6a1dbee68
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+++ b/dom/media/mediasession/test/browser_active_mediasession_among_tabs.js
@@ -0,0 +1,201 @@
+/* eslint-disable no-undef */
+"use strict";
+
+const PAGE =
+  "https://example.com/browser/dom/media/mediasession/test/file_media_session.html";
+
+const ACTION = "previoustrack";
+
+add_task(async function setupTestingPref() {
+  await SpecialPowers.pushPrefEnv({
+    set: [
+      ["dom.media.mediasession.enabled", true],
+      ["media.mediacontrol.testingevents.enabled", true],
+    ],
+  });
+});
+
+/**
+ * When multiple tabs are all having media session, the latest created one would
+ * become an active session. When the active media session is destroyed via
+ * closing the tab, the previous active session would become current active
+ * session again.
+ */
+add_task(async function testActiveSessionWhenClosingTab() {
+  info(`open tab1 and load media session test page`);
+  const tab1 = await BrowserTestUtils.openNewForegroundTab(gBrowser, PAGE);
+  await startMediaPlaybackAndWaitMedisSessionBecomeActiveSession(tab1);
+
+  info(`pressing '${ACTION}' key`);
+  MediaControlService.generateMediaControlKey(ACTION);
+
+  info(`session in tab1 should become active session`);
+  await checkIfActionReceived(tab1, ACTION);
+
+  info(`open tab2 and load media session test page`);
+  const tab2 = await BrowserTestUtils.openNewForegroundTab(gBrowser, PAGE);
+  await startMediaPlaybackAndWaitMedisSessionBecomeActiveSession(tab2);
+
+  info(`pressing '${ACTION}' key`);
+  MediaControlService.generateMediaControlKey(ACTION);
+
+  info(`session in tab2 should become active session`);
+  await checkIfActionReceived(tab2, ACTION);
+  await checkIfActionNotReceived(tab1, ACTION);
+
+  info(`remove tab2`);
+  const controllerChanged = waitUntilMainMediaControllerChanged();
+  BrowserTestUtils.removeTab(tab2);
+  await controllerChanged;
+
+  info(`pressing '${ACTION}' key`);
+  MediaControlService.generateMediaControlKey(ACTION);
+
+  info(`session in tab1 should become active session again`);
+  await checkIfActionReceived(tab1, ACTION);
+
+  info(`remove tab1`);
+  BrowserTestUtils.removeTab(tab1);
+});
+
+/**
+ * This test is similar with `testActiveSessionWhenClosingTab`, the difference
+ * is that the way we use to destroy active session is via naviagation, not
+ * closing tab.
+ */
+add_task(async function testActiveSessionWhenNavigatingTab() {
+  info(`open tab1 and load media session test page`);
+  const tab1 = await BrowserTestUtils.openNewForegroundTab(gBrowser, PAGE);
+  await startMediaPlaybackAndWaitMedisSessionBecomeActiveSession(tab1);
+
+  info(`pressing '${ACTION}' key`);
+  MediaControlService.generateMediaControlKey(ACTION);
+
+  info(`session in tab1 should become active session`);
+  await checkIfActionReceived(tab1, ACTION);
+
+  info(`open tab2 and load media session test page`);
+  const tab2 = await BrowserTestUtils.openNewForegroundTab(gBrowser, PAGE);
+  await startMediaPlaybackAndWaitMedisSessionBecomeActiveSession(tab2);
+
+  info(`pressing '${ACTION}' key`);
+  MediaControlService.generateMediaControlKey(ACTION);
+
+  info(`session in tab2 should become active session`);
+  await checkIfActionReceived(tab2, ACTION);
+  await checkIfActionNotReceived(tab1, ACTION);
+
+  info(`navigate tab2 to blank page`);
+  const controllerChanged = waitUntilMainMediaControllerChanged();
+  BrowserTestUtils.loadURIString(tab2.linkedBrowser, "about:blank");
+  await controllerChanged;
+
+  info(`pressing '${ACTION}' key`);
+  MediaControlService.generateMediaControlKey(ACTION);
+
+  info(`session in tab1 should become active session`);
+  await checkIfActionReceived(tab1, ACTION);
+
+  info(`remove tabs`);
+  BrowserTestUtils.removeTab(tab1);
+  BrowserTestUtils.removeTab(tab2);
+});
+
+/**
+ * If we create a media session in a tab where no any playing media exists, then
+ * that session would not involve in global active media session selection. The
+ * current active media session would remain unchanged.
+ */
+add_task(async function testCreatingSessionWithoutPlayingMedia() {
+  info(`open tab1 and load media session test page`);
+  const tab1 = await BrowserTestUtils.openNewForegroundTab(gBrowser, PAGE);
+  await startMediaPlaybackAndWaitMedisSessionBecomeActiveSession(tab1);
+
+  info(`pressing '${ACTION}' key`);
+  MediaControlService.generateMediaControlKey(ACTION);
+
+  info(`session in tab1 should become active session`);
+  await checkIfActionReceived(tab1, ACTION);
+
+  info(`open tab2 and load media session test page`);
+  const tab2 = await BrowserTestUtils.openNewForegroundTab(gBrowser, PAGE);
+
+  info(`pressing '${ACTION}' key`);
+  MediaControlService.generateMediaControlKey(ACTION);
+
+  info(
+    `session in tab1 is still an active session because there is no media playing in tab2`
+  );
+  await checkIfActionReceived(tab1, ACTION);
+  await checkIfActionNotReceived(tab2, ACTION);
+
+  info(`remove tabs`);
+  BrowserTestUtils.removeTab(tab1);
+  BrowserTestUtils.removeTab(tab2);
+});
+
+/**
+ * The following are helper functions
+ */
+async function startMediaPlaybackAndWaitMedisSessionBecomeActiveSession(tab) {
+  await Promise.all([
+    BrowserUtils.promiseObserved("active-media-session-changed"),
+    SpecialPowers.spawn(tab.linkedBrowser, [], () => {
+      const video = content.document.getElementById("testVideo");
+      if (!video) {
+        ok(false, `can't get the media element!`);
+      }
+      video.play();
+    }),
+  ]);
+}
+
+async function checkIfActionReceived(tab, action) {
+  await SpecialPowers.spawn(tab.linkedBrowser, [action], expectedAction => {
+    return new Promise(resolve => {
+      const result = content.document.getElementById("result");
+      if (!result) {
+        ok(false, `can't get the element for showing result!`);
+      }
+
+      function checkAction() {
+        is(
+          result.innerHTML,
+          expectedAction,
+          `received '${expectedAction}' correctly`
+        );
+        // Reset the result after finishing checking result, then we can dispatch
+        // same action again without worrying about previous result.
+        result.innerHTML = "";
+        resolve();
+      }
+
+      if (result.innerHTML == "") {
+        info(`wait until receiving action`);
+        result.addEventListener("actionChanged", () => checkAction(), {
+          once: true,
+        });
+      } else {
+        checkAction();
+      }
+    });
+  });
+}
+
+async function checkIfActionNotReceived(tab, action) {
+  await SpecialPowers.spawn(tab.linkedBrowser, [action], expectedAction => {
+    return new Promise(resolve => {
+      const result = content.document.getElementById("result");
+      if (!result) {
+        ok(false, `can't get the element for showing result!`);
+      }
+      is(result.innerHTML, "", `should not receive any action`);
+      ok(result.innerHTML != expectedAction, `not receive '${expectedAction}'`);
+      resolve();
+    });
+  });
+}
+
+function waitUntilMainMediaControllerChanged() {
+  return BrowserUtils.promiseObserved("main-media-controller-changed");
+}