fix(dropdown): do not call on-toggle initially

Closes #2021

Author: bekos

src/dropdown/dropdown.js

@@ -78,7 +78,7 @@ angular.module('ui.bootstrap.dropdown', [])
     }
   };
 
-  scope.$watch('isOpen', function( isOpen ) {
+  scope.$watch('isOpen', function( isOpen, wasOpen ) {
     $animate[isOpen ? 'addClass' : 'removeClass'](self.$element, openClass);
 
     if ( isOpen ) {
@@ -89,7 +89,9 @@ angular.module('ui.bootstrap.dropdown', [])
     }
 
     setIsOpen($scope, isOpen);
-    toggleInvoker($scope, { open: !!isOpen });
+    if (angular.isDefined(wasOpen) && isOpen !== wasOpen) {
+      toggleInvoker($scope, { open: !!isOpen });
+    }
   });
 
   $scope.$on('$locationChangeSuccess', function() {

src/dropdown/test/dropdown.spec.js

@@ -212,16 +212,18 @@ describe('dropdownToggle', function() {
   describe('`on-toggle`', function() {
     beforeEach(function() {
       $rootScope.toggleHandler = jasmine.createSpy('toggleHandler');
-      element = $compile('<li class="dropdown" on-toggle="toggleHandler(open)"><a dropdown-toggle></a><ul><li>Hello</li></ul></li>')($rootScope);
+      $rootScope.isopen = false;
+      element = $compile('<li class="dropdown" on-toggle="toggleHandler(open)"  is-open="isopen"><a dropdown-toggle></a><ul><li>Hello</li></ul></li>')($rootScope);
       $rootScope.$digest();
     });
 
-    it('should be called initially', function() {
-      expect($rootScope.toggleHandler).toHaveBeenCalledWith(false);
+    it('should not have been called initially', function() {
+      expect($rootScope.toggleHandler).not.toHaveBeenCalled();
     });
 
     it('should call it correctly when toggles', function() {
-      clickDropdownToggle();
+      $rootScope.isopen = true;
+      $rootScope.$digest();
       expect($rootScope.toggleHandler).toHaveBeenCalledWith(true);
 
       clickDropdownToggle();
@@ -237,8 +239,8 @@ describe('dropdownToggle', function() {
       $rootScope.$digest();
     });
 
-    it('should be called initially with true', function() {
-      expect($rootScope.toggleHandler).toHaveBeenCalledWith(true);
+    it('should not have been called initially', function() {
+      expect($rootScope.toggleHandler).not.toHaveBeenCalled();
     });
 
     it('should call it correctly when toggles', function() {