--- a/browser/modules/UITour.jsm
+++ b/browser/modules/UITour.jsm
@@ -21,16 +21,17 @@ XPCOMUtils.defineLazyModuleGetter(this, 
   "resource:///modules/CustomizableUI.jsm");
 XPCOMUtils.defineLazyModuleGetter(this, "UITelemetry",
   "resource://gre/modules/UITelemetry.jsm");
 XPCOMUtils.defineLazyModuleGetter(this, "BrowserUITelemetry",
   "resource:///modules/BrowserUITelemetry.jsm");
 
 
 const UITOUR_PERMISSION   = "uitour";
+const PREF_TEST_WHITELIST = "browser.uitour.testingOrigins";
 const PREF_SEENPAGEIDS    = "browser.uitour.seenPageIDs";
 const MAX_BUTTONS         = 4;
 
 const BUCKET_NAME         = "UITour";
 const BUCKET_TIMESTEPS    = [
   1 * 60 * 1000, // Until 1 minute after tab is closed/inactive.
   3 * 60 * 1000, // Until 3 minutes after tab is closed/inactive.
   10 * 60 * 1000, // Until 10 minutes after tab is closed/inactive.
@@ -615,30 +616,52 @@ this.UITour = {
                            .getInterface(Ci.nsIWebNavigation)
                            .QueryInterface(Ci.nsIDocShellTreeItem)
                            .rootTreeItem
                            .QueryInterface(Ci.nsIInterfaceRequestor)
                            .getInterface(Ci.nsIDOMWindow)
                            .wrappedJSObject;
   },
 
+  isTestingOrigin: function(aURI) {
+    if (Services.prefs.getPrefType(PREF_TEST_WHITELIST) != Services.prefs.PREF_STRING) {
+      return false;
+    }
+
+    // Add any testing origins (comma-seperated) to the whitelist for the session.
+    for (let origin of Services.prefs.getCharPref(PREF_TEST_WHITELIST).split(",")) {
+      try {
+        let testingURI = Services.io.newURI(origin, null, null);
+        if (aURI.prePath == testingURI.prePath) {
+          return true;
+        }
+      } catch (ex) {
+        Cu.reportError(ex);
+      }
+    }
+    return false;
+  },
+
   ensureTrustedOrigin: function(aDocument) {
     if (aDocument.defaultView.top != aDocument.defaultView)
       return false;
 
     let uri = aDocument.documentURIObject;
 
     if (uri.schemeIs("chrome"))
       return true;
 
     if (!this.isSafeScheme(uri))
       return false;
 
     let permission = Services.perms.testPermission(uri, UITOUR_PERMISSION);
-    return permission == Services.perms.ALLOW_ACTION;
+    if (permission == Services.perms.ALLOW_ACTION)
+      return true;
+
+    return this.isTestingOrigin(uri);
   },
 
   isSafeScheme: function(aURI) {
     let allowedSchemes = new Set(["https", "about"]);
     if (!Services.prefs.getBoolPref("browser.uitour.requireSecure"))
       allowedSchemes.add("http");
 
     if (!allowedSchemes.has(aURI.scheme))

--- a/browser/modules/test/browser_UITour.js
+++ b/browser/modules/test/browser_UITour.js
@@ -20,16 +20,33 @@ let tests = [
       ise(bookmarksMenu.open, false, "Bookmark menu should initially be closed");
 
       gContentAPI.showMenu("bookmarks");
       ise(bookmarksMenu.open, false, "Bookmark menu should not open on a untrusted host");
 
       done();
     }, "http://mochi.test:8888/");
   },
+  function test_testing_host(done) {
+    // Add two testing origins intentionally surrounded by whitespace to be ignored.
+    Services.prefs.setCharPref("browser.uitour.testingOrigins",
+                               "https://test1.example.com, https://test2.example.com:443 ");
+
+    registerCleanupFunction(() => {
+      Services.prefs.clearUserPref("browser.uitour.testingOrigins");
+    });
+    function callback(result) {
+      ok(result, "Callback should be called on a testing origin");
+      done();
+    }
+
+    loadUITourTestPage(function() {
+      gContentAPI.getConfiguration("appinfo", callback);
+    }, "https://test2.example.com/");
+  },
   function test_unsecure_host(done) {
     loadUITourTestPage(function() {
       let bookmarksMenu = document.getElementById("bookmarks-menu-button");
       ise(bookmarksMenu.open, false, "Bookmark menu should initially be closed");
 
       gContentAPI.showMenu("bookmarks");
       ise(bookmarksMenu.open, false, "Bookmark menu should not open on a unsecure host");