diff --git a/js/tabs.js b/js/tabs.js
index 6dfa330..0735869 100644
--- a/js/tabs.js
+++ b/js/tabs.js
@@ -1,26 +1,28 @@
 var tabs = angular.module('tabs', []);
 
 
+var TabsController = function($scope, $element) {
+  var panes = $scope.panes = [];
+
+  $scope.select = function(pane) {
+    angular.forEach(panes, function(pane) {
+      pane.selected = false;
+    });
+    pane.selected = true;
+  };
+
+  this.addPane = function(pane) {
+    if (!panes.length) $scope.select(pane);
+    panes.push(pane);
+  };
+};
+
 tabs.directive('tabs', function() {
   return {
     restrict: 'E',
     transclude: true,
     scope: {},
-    controller: function($scope, $element) {
-      var panes = $scope.panes = [];
-
-      $scope.select = function(pane) {
-        angular.forEach(panes, function(pane) {
-          pane.selected = false;
-        });
-        pane.selected = true;
-      };
-
-      this.addPane = function(pane) {
-        if (!panes.length) $scope.select(pane);
-        panes.push(pane);
-      };
-    },
+    controller: TabsController,
     // templateUrl: 'tpl/tabs.html',
     template:
       '<div class="tabbable">' +
diff --git a/test/tabsSpec.js b/test/tabsSpec.js
index 3c2cd20..f867879 100644
--- a/test/tabsSpec.js
+++ b/test/tabsSpec.js
@@ -85,3 +85,77 @@ describe('tabs', function() {
     expect(contents.eq(1)).toHaveClass('active');
   });
 });
+
+
+describe('tabs controller', function() {
+  var scope, ctrl;
+
+  beforeEach(inject(function($controller, $rootScope) {
+    scope = $rootScope;
+
+    // instantiate the controller stand-alone, without the directive
+    ctrl = $controller(TabsController, {$scope: scope, $element: null});
+  }));
+
+
+  describe('select', function() {
+
+    it('should mark given pane selected', function() {
+      var pane = {};
+
+      scope.select(pane);
+      expect(pane.selected).toBe(true);
+    });
+
+
+    it('should deselect other panes', function() {
+      var pane1 = {}, pane2 = {}, pane3 = {};
+
+      ctrl.addPane(pane1);
+      ctrl.addPane(pane2);
+      ctrl.addPane(pane3);
+
+      scope.select(pane1);
+      expect(pane1.selected).toBe(true);
+      expect(pane2.selected).toBe(false);
+      expect(pane3.selected).toBe(false);
+
+      scope.select(pane2);
+      expect(pane1.selected).toBe(false);
+      expect(pane2.selected).toBe(true);
+      expect(pane3.selected).toBe(false);
+
+      scope.select(pane3);
+      expect(pane1.selected).toBe(false);
+      expect(pane2.selected).toBe(false);
+      expect(pane3.selected).toBe(true);
+    });
+  });
+
+
+  describe('addPane', function() {
+
+    it('should append pane', function() {
+      var pane1 = {}, pane2 = {};
+
+      expect(scope.panes).toEqual([]);
+
+      ctrl.addPane(pane1);
+      expect(scope.panes).toEqual([pane1]);
+
+      ctrl.addPane(pane2);
+      expect(scope.panes).toEqual([pane1, pane2]);
+    });
+
+
+    it('should select the first one', function() {
+      var pane1 = {}, pane2 = {};
+
+      ctrl.addPane(pane1);
+      expect(pane1.selected).toBe(true);
+
+      ctrl.addPane(pane2);
+      expect(pane1.selected).toBe(true);
+    });
+  });
+});