1 files changed, 116 insertions, 0 deletions
diff --git a/js/xpconnect/tests/unit/head_watchdog.js b/js/xpconnect/tests/unit/head_watchdog.js
new file mode 100644
index 0000000000..f977c1f129
--- /dev/null
+++ b/js/xpconnect/tests/unit/head_watchdog.js
@@ -0,0 +1,116 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+//
+// Pref management.
+//
+
+var {PromiseTestUtils} = ChromeUtils.importESModule("resource://testing-common/PromiseTestUtils.sys.mjs");
+
+///////////////////
+//
+// Whitelisting these tests.
+// As part of bug 1077403, the shutdown crash should be fixed.
+//
+// These tests may crash intermittently on shutdown if the DOM Promise uncaught
+// rejection observers are still registered when the watchdog operates.
+PromiseTestUtils.thisTestLeaksUncaughtRejectionsAndShouldBeFixed();
+
+var gPrefs = Cc["@mozilla.org/preferences-service;1"].getService(Ci.nsIPrefBranch);
+
+function setWatchdogEnabled(enabled) {
+  gPrefs.setBoolPref("dom.use_watchdog", enabled);
+}
+
+function isWatchdogEnabled() {
+  return gPrefs.getBoolPref("dom.use_watchdog");
+}
+
+function setScriptTimeout(seconds) {
+  var oldTimeout = gPrefs.getIntPref("dom.max_script_run_time");
+  gPrefs.setIntPref("dom.max_script_run_time", seconds);
+  return oldTimeout;
+}
+
+//
+// Utilities.
+//
+
+function busyWait(ms) {
+  var start = new Date();
+  while ((new Date()) - start < ms) {}
+}
+
+function do_log_info(aMessage)
+{
+  print("TEST-INFO | " + _TEST_FILE + " | " + aMessage);
+}
+
+// We don't use do_execute_soon, because that inserts a
+// do_test_{pending,finished} pair that gets screwed up when we terminate scripts
+// from the operation callback.
+function executeSoon(fn) {
+  var tm = Cc["@mozilla.org/thread-manager;1"].getService(Ci.nsIThreadManager);
+  tm.dispatchToMainThread({run: fn});
+}
+
+//
+// Asynchronous watchdog diagnostics.
+//
+// When running, the watchdog wakes up every second, and fires the operation
+// callback if the script has been running for >= the minimum script timeout.
+// As such, if the script timeout is 1 second, a script should never be able to
+// run for two seconds or longer without servicing the operation callback.
+// We wait 3 seconds, just to be safe.
+//
+
+function checkWatchdog(expectInterrupt) {
+  var oldTimeout = setScriptTimeout(1);
+  var lastWatchdogWakeup = Cu.getWatchdogTimestamp("WatchdogWakeup");
+
+  return new Promise(resolve => {
+    let inBusyWait = false;
+    setInterruptCallback(function() {
+      // If the watchdog didn't actually trigger the operation callback, ignore
+      // this call. This allows us to test the actual watchdog behavior without
+      // interference from other sites where we trigger the operation callback.
+      if (lastWatchdogWakeup == Cu.getWatchdogTimestamp("WatchdogWakeup")) {
+        return true;
+      }
+      if (!inBusyWait) {
+        Assert.ok(true, "Not in busy wait, ignoring interrupt callback");
+        return true;
+      }
+
+      Assert.ok(expectInterrupt, "Interrupt callback fired");
+      setInterruptCallback(undefined);
+      setScriptTimeout(oldTimeout);
+      // Schedule the promise for resolution before we kill this script.
+      executeSoon(resolve);
+      return false;
+    });
+
+    executeSoon(function() {
+      inBusyWait = true;
+      busyWait(3000);
+      inBusyWait = false;
+      Assert.ok(!expectInterrupt, "Interrupt callback didn't fire");
+      setInterruptCallback(undefined);
+      setScriptTimeout(oldTimeout);
+      resolve();
+    });
+  });
+}
+
+function run_test() {
+
+  // Run async.
+  do_test_pending();
+
+  // Run the async function.
+  testBody().then(() => {
+    do_test_finished();
+  });
+}
+