1 files changed, 118 insertions, 0 deletions
diff --git a/browser/components/sessionstore/test/browser_not_collect_when_idle.js b/browser/components/sessionstore/test/browser_not_collect_when_idle.js
new file mode 100644
index 0000000000..c4a49ab7b7
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+++ b/browser/components/sessionstore/test/browser_not_collect_when_idle.js
@@ -0,0 +1,118 @@
+/** Test for Bug 1305950 **/
+
+const { MockRegistrar } = ChromeUtils.importESModule(
+  "resource://testing-common/MockRegistrar.sys.mjs"
+);
+
+// The mock idle service.
+var idleService = {
+  _observers: new Set(),
+  _activity: {
+    addCalls: [],
+    removeCalls: [],
+    observerFires: [],
+  },
+
+  _reset() {
+    this._observers.clear();
+    this._activity.addCalls = [];
+    this._activity.removeCalls = [];
+    this._activity.observerFires = [];
+  },
+
+  _fireObservers(state) {
+    for (let observer of this._observers.values()) {
+      observer.observe(observer, state, null);
+      this._activity.observerFires.push(state);
+    }
+  },
+
+  QueryInterface: ChromeUtils.generateQI(["nsIUserIdleService"]),
+  idleTime: 19999,
+
+  addIdleObserver(observer, time) {
+    this._observers.add(observer);
+    this._activity.addCalls.push(time);
+  },
+
+  removeIdleObserver(observer, time) {
+    this._observers.delete(observer);
+    this._activity.removeCalls.push(time);
+  },
+};
+
+add_task(async function testIntervalChanges() {
+  const PREF_SS_INTERVAL = 2000;
+
+  // We speed up the interval between session saves to ensure that the test
+  // runs quickly.
+  Services.prefs.setIntPref("browser.sessionstore.interval", PREF_SS_INTERVAL);
+
+  // Increase `idleDelay` to 1 day to update the pre-registered idle observer
+  // in "real" idle service to avoid possible interference, especially for the
+  // CI server environment.
+  Services.prefs.setIntPref("browser.sessionstore.idleDelay", 86400);
+
+  // Mock an idle service.
+  let fakeIdleService = MockRegistrar.register(
+    "@mozilla.org/widget/useridleservice;1",
+    idleService
+  );
+  idleService._reset();
+
+  registerCleanupFunction(function () {
+    Services.prefs.clearUserPref("browser.sessionstore.interval");
+    MockRegistrar.unregister(fakeIdleService);
+  });
+
+  // Hook idle/active observer to mock idle service by changing pref `idleDelay`
+  // to a whatever value, which will not be used.
+  Services.prefs.setIntPref("browser.sessionstore.idleDelay", 5000);
+
+  // Wait a `sessionstore-state-write-complete` event from any previous
+  // scheduled state write. This is needed since the `_lastSaveTime` in
+  // runDelayed() should be set at least once, or the `_isIdle` flag will not
+  // become effective.
+  info("Waiting for sessionstore-state-write-complete notification");
+  await TestUtils.topicObserved("sessionstore-state-write-complete");
+
+  info(
+    "Got the sessionstore-state-write-complete notification, now testing idle mode"
+  );
+
+  // Enter the "idle mode" (raise the `_isIdle` flag) by firing idle
+  // observer of mock idle service.
+  idleService._fireObservers("idle");
+
+  // Cancel any possible state save, which is not related with this test to
+  // avoid interference.
+  SessionSaver.cancel();
+
+  let p1 = promiseSaveState();
+
+  // Schedule a state write, which is expeced to be postponed after about
+  // `browser.sessionstore.interval.idle` ms, since the idle flag was just set.
+  SessionSaver.runDelayed(0);
+
+  // We expect `p1` hits the timeout.
+  await Assert.rejects(
+    p1,
+    /Save state timeout/,
+    "[Test 1A] No state write during idle."
+  );
+
+  // Test again for better reliability. Same, we expect following promise hits
+  // the timeout.
+  await Assert.rejects(
+    promiseSaveState(),
+    /Save state timeout/,
+    "[Test 1B] Again: No state write during idle."
+  );
+
+  // Back to the active mode.
+  info("Start to test active mode...");
+  idleService._fireObservers("active");
+
+  info("[Test 2] Waiting for sessionstore-state-write-complete during active");
+  await TestUtils.topicObserved("sessionstore-state-write-complete");
+});