michael@0: /* This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: Cu.import("resource://gre/modules/Promise.jsm");
michael@0: 
michael@0: let cs = Cc["@mozilla.org/consoleservice;1"].
michael@0:   getService(Ci.nsIConsoleService);
michael@0: let ps = Cc["@mozilla.org/preferences-service;1"].
michael@0:   getService(Ci.nsIPrefService);
michael@0: 
michael@0: function makeBuffer(length) {
michael@0:   return new Array(length + 1).join('x');
michael@0: }
michael@0: 
michael@0: /**
michael@0:  * @resolves |true| if execution proceeded without warning,
michael@0:  * |false| if there was a warning.
michael@0:  */
michael@0: function checkWarning(pref, buffer) {
michael@0:   let deferred = Promise.defer();
michael@0:   let complete = false;
michael@0:   let listener = {
michael@0:     observe: function(event) {
michael@0:       let message = event.message;
michael@0:       if (!(message.startsWith("Warning: attempting to write")
michael@0:             && message.contains(pref))) {
michael@0:         return;
michael@0:       }
michael@0:       if (complete) {
michael@0:         return;
michael@0:       }
michael@0:       complete = true;
michael@0:       do_print("Warning while setting " + pref);
michael@0:       cs.unregisterListener(listener);
michael@0:       deferred.resolve(true);
michael@0:     }
michael@0:   };
michael@0:   do_timeout(1000, function() {
michael@0:     if (complete) {
michael@0:       return;
michael@0:     }
michael@0:     complete = true;
michael@0:     do_print("No warning while setting " + pref);
michael@0:     cs.unregisterListener(listener);
michael@0:     deferred.resolve(false);
michael@0:   });
michael@0:   cs.registerListener(listener);
michael@0:   ps.setCharPref(pref, buffer);
michael@0:   return deferred.promise;
michael@0: }
michael@0: 
michael@0: function run_test() {
michael@0:   run_next_test();
michael@0: }
michael@0: 
michael@0: add_task(function() {
michael@0:   // Simple change, shouldn't cause a warning
michael@0:   do_print("Checking that a simple change doesn't cause a warning");
michael@0:   let buf = makeBuffer(100);
michael@0:   let warned = yield checkWarning("string.accept", buf);
michael@0:   do_check_false(warned);
michael@0: 
michael@0:   // Large change, should cause a warning
michael@0:   do_print("Checking that a large change causes a warning");
michael@0:   buf = makeBuffer(32 * 1024);
michael@0:   warned = yield checkWarning("string.warn", buf);
michael@0:   do_check_true(warned);
michael@0: });