diff -r 000000000000 -r 6474c204b198 browser/devtools/webconsole/test/browser_webconsole_expandable_timestamps.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/browser/devtools/webconsole/test/browser_webconsole_expandable_timestamps.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,57 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+// Test for the message timestamps option: check if the preference toggles the
+// display of messages in the console output. See bug 722267.
+
+function test()
+{
+  const PREF_MESSAGE_TIMESTAMP = "devtools.webconsole.timestampMessages";
+  let hud;
+
+  registerCleanupFunction(() => {
+    Services.prefs.clearUserPref(PREF_MESSAGE_TIMESTAMP);
+  });
+
+  addTab("data:text/html;charset=utf-8,Web Console test for bug 722267 - " +
+         "preference for toggling timestamps in messages");
+
+  browser.addEventListener("load", function tabLoad() {
+    browser.removeEventListener("load", tabLoad, true);
+    openConsole(null, consoleOpened);
+  }, true);
+
+  function consoleOpened(aHud)
+  {
+    hud = aHud;
+
+    info("console opened");
+    let prefValue = Services.prefs.getBoolPref(PREF_MESSAGE_TIMESTAMP);
+    ok(!prefValue, "messages have no timestamp by default (pref check)");
+    ok(hud.outputNode.classList.contains("hideTimestamps"),
+       "messages have no timestamp (class name check)");
+
+    let toolbox = gDevTools.getToolbox(hud.target);
+    toolbox.selectTool("options").then(onOptionsPanelSelected);
+  }
+
+  function onOptionsPanelSelected(panel)
+  {
+    info("options panel opened");
+
+    gDevTools.once("pref-changed", onPrefChanged);
+
+    let checkbox = panel.panelDoc.getElementById("webconsole-timestamp-messages");
+    checkbox.click();
+  }
+
+  function onPrefChanged()
+  {
+    info("pref changed");
+    let prefValue = Services.prefs.getBoolPref(PREF_MESSAGE_TIMESTAMP);
+    ok(prefValue, "messages have timestamps (pref check)");
+    ok(!hud.outputNode.classList.contains("hideTimestamps"),
+       "messages have timestamps (class name check)");
+    finishTest();
+  }
+}