diff -r 000000000000 -r 6474c204b198 toolkit/devtools/server/tests/unit/testactors.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/toolkit/devtools/server/tests/unit/testactors.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,117 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+var gTestGlobals = [];
+DebuggerServer.addTestGlobal = function(aGlobal) {
+  gTestGlobals.push(aGlobal);
+};
+
+// A mock tab list, for use by tests. This simply presents each global in
+// gTestGlobals as a tab, and the list is fixed: it never calls its
+// onListChanged handler.
+//
+// As implemented now, we consult gTestGlobals when we're constructed, not
+// when we're iterated over, so tests have to add their globals before the
+// root actor is created.
+function TestTabList(aConnection) {
+  this.conn = aConnection;
+
+  // An array of actors for each global added with
+  // DebuggerServer.addTestGlobal.
+  this._tabActors = [];
+
+  // A pool mapping those actors' names to the actors.
+  this._tabActorPool = new ActorPool(aConnection);
+
+  for (let global of gTestGlobals) {
+    let actor = new TestTabActor(aConnection, global);
+    actor.selected = false;
+    this._tabActors.push(actor);
+    this._tabActorPool.addActor(actor);
+  }
+  if (this._tabActors.length > 0) {
+    this._tabActors[0].selected = true;
+  }
+
+  aConnection.addActorPool(this._tabActorPool);
+}
+
+TestTabList.prototype = {
+  constructor: TestTabList,
+  getList: function () {
+    return promise.resolve([tabActor for (tabActor of this._tabActors)]);
+  }
+};
+
+function createRootActor(aConnection)
+{
+  let root = new RootActor(aConnection,
+                           { tabList: new TestTabList(aConnection) });
+  root.applicationType = "xpcshell-tests";
+  return root;
+}
+
+function TestTabActor(aConnection, aGlobal)
+{
+  this.conn = aConnection;
+  this._global = aGlobal;
+  this._global.wrappedJSObject = aGlobal;
+  this._threadActor = new ThreadActor(this, this._global);
+  this.conn.addActor(this._threadActor);
+  this._attached = false;
+  this._extraActors = {};
+}
+
+TestTabActor.prototype = {
+  constructor: TestTabActor,
+  actorPrefix: "TestTabActor",
+
+  get window() {
+    return { wrappedJSObject: this._global };
+  },
+
+  get url() {
+    return this._global.__name;
+  },
+
+  form: function() {
+    let response = { actor: this.actorID, title: this._global.__name };
+
+    // Walk over tab actors added by extensions and add them to a new ActorPool.
+    let actorPool = new ActorPool(this.conn);
+    this._createExtraActors(DebuggerServer.tabActorFactories, actorPool);
+    if (!actorPool.isEmpty()) {
+      this._tabActorPool = actorPool;
+      this.conn.addActorPool(this._tabActorPool);
+    }
+
+    this._appendExtraActors(response);
+
+    return response;
+  },
+
+  onAttach: function(aRequest) {
+    this._attached = true;
+
+    let response = { type: "tabAttached", threadActor: this._threadActor.actorID };
+    this._appendExtraActors(response);
+
+    return response;
+  },
+
+  onDetach: function(aRequest) {
+    if (!this._attached) {
+      return { "error":"wrongState" };
+    }
+    return { type: "detached" };
+  },
+
+  /* Support for DebuggerServer.addTabActor. */
+  _createExtraActors: createExtraActors,
+  _appendExtraActors: appendExtraActors
+};
+
+TestTabActor.prototype.requestTypes = {
+  "attach": TestTabActor.prototype.onAttach,
+  "detach": TestTabActor.prototype.onDetach
+};