diff -r 000000000000 -r 6474c204b198 dom/browser-element/mochitest/browserElement_Alert.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/dom/browser-element/mochitest/browserElement_Alert.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,161 @@
+/* Any copyright is dedicated to the public domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+// Test that alert works.
+"use strict";
+
+SimpleTest.waitForExplicitFinish();
+browserElementTestHelpers.setEnabledPref(true);
+browserElementTestHelpers.addPermission();
+
+var numPendingChildTests = 0;
+var iframe;
+var mm;
+
+function runTest() {
+  iframe = document.createElement('iframe');
+  SpecialPowers.wrap(iframe).mozbrowser = true;
+  document.body.appendChild(iframe);
+
+  mm = SpecialPowers.getBrowserFrameMessageManager(iframe);
+  mm.addMessageListener('test-success', function(msg) {
+    numPendingChildTests--;
+    ok(true, SpecialPowers.wrap(msg).json);
+  });
+  mm.addMessageListener('test-fail', function(msg) {
+    numPendingChildTests--;
+    ok(false, SpecialPowers.wrap(msg).json);
+  });
+
+  // Wait for the initial load to finish, then navigate the page, then wait
+  // for that load to finish, then start test1.
+  iframe.addEventListener('mozbrowserloadend', function loadend() {
+    iframe.removeEventListener('mozbrowserloadend', loadend);
+    iframe.src = browserElementTestHelpers.emptyPage1;
+
+    iframe.addEventListener('mozbrowserloadend', function loadend2() {
+      iframe.removeEventListener('mozbrowserloadend', loadend2);
+      SimpleTest.executeSoon(test1);
+    });
+  });
+
+}
+
+function test1() {
+  iframe.addEventListener('mozbrowsershowmodalprompt', test2);
+
+  // Do window.alert within the iframe, then modify the global |testState|
+  // after the alert.
+  var script = 'data:,\
+    testState = 0; \
+    content.alert("Hello, world!"); \
+    testState = 1; \
+  ';
+
+  mm.loadFrameScript(script, /* allowDelayedLoad = */ false);
+
+  // Triggers a mozbrowsershowmodalprompt event, which sends us down to test2.
+}
+
+// test2 is a mozbrowsershowmodalprompt listener.
+function test2(e) {
+  iframe.removeEventListener("mozbrowsershowmodalprompt", test2);
+
+  is(e.detail.message, 'Hello, world!');
+  e.preventDefault(); // cause the alert to block.
+
+  SimpleTest.executeSoon(function() { test2a(e); });
+}
+
+function test2a(e) {
+  // The iframe should be blocked on the alert call at the moment, so testState
+  // should still be 0.
+  var script = 'data:,\
+    if (testState === 0) { \
+      sendAsyncMessage("test-success", "1: Correct testState"); \
+    } \
+    else { \
+      sendAsyncMessage("test-fail", "1: Wrong testState: " + testState); \
+    }';
+
+  mm.loadFrameScript(script, /* allowDelayedLoad = */ false);
+  numPendingChildTests++;
+
+  waitForPendingTests(function() { test3(e); });
+}
+
+function test3(e) {
+  // Now unblock the iframe and check that the script completed.
+  e.detail.unblock();
+
+  var script2 = 'data:,\
+    if (testState === 1) { \
+      sendAsyncMessage("test-success", "2: Correct testState"); \
+    } \
+    else { \
+      sendAsyncMessage("test-try-again", "2: Wrong testState (for now): " + testState); \
+    }';
+
+  // Urgh.  e.unblock() didn't necessarily unblock us immediately, so we have
+  // to spin and wait.
+  function onTryAgain() {
+    SimpleTest.executeSoon(function() {
+      //dump('onTryAgain\n');
+      mm.loadFrameScript(script2, /* allowDelayedLoad = */ false);
+    });
+  }
+
+  mm.addMessageListener('test-try-again', onTryAgain);
+  numPendingChildTests++;
+
+  onTryAgain();
+  waitForPendingTests(function() { test4(); });
+}
+
+function test4() {
+  // Navigate the iframe while an alert is pending.  This shouldn't screw
+  // things up.
+
+  iframe.addEventListener("mozbrowsershowmodalprompt", test5);
+
+  var script = 'data:,content.alert("test4");';
+  mm.loadFrameScript(script, /* allowDelayedLoad = */ false);
+}
+
+// test4 is a mozbrowsershowmodalprompt listener.
+function test5(e) {
+  iframe.removeEventListener('mozbrowsershowmodalprompt', test4);
+
+  is(e.detail.message, 'test4');
+  e.preventDefault(); // cause the page to block.
+
+  SimpleTest.executeSoon(test5a);
+}
+
+function test5a() {
+  iframe.addEventListener('mozbrowserloadend', test5b);
+  iframe.src = browserElementTestHelpers.emptyPage2;
+}
+
+function test5b() {
+  iframe.removeEventListener('mozbrowserloadend', test5b);
+  SimpleTest.finish();
+}
+
+var prevNumPendingTests = null;
+function waitForPendingTests(next) {
+  if (numPendingChildTests !== prevNumPendingTests) {
+    dump("Waiting for end; " + numPendingChildTests + " pending tests\n");
+    prevNumPendingTests = numPendingChildTests;
+  }
+
+  if (numPendingChildTests > 0) {
+    SimpleTest.executeSoon(function() { waitForPendingTests(next); });
+    return;
+  }
+
+  prevNumPendingTests = null;
+  next();
+}
+
+addEventListener('testready', runTest);