fix(ngClass): keep track of old ngClass value manually

ngClassWatchAction, when called as a $watch function, gets the wrong old
value after it has been invoked previously due to observation of the
interpolated class attribute. As a result it doesn't remove classes
properly. Keeping track of the old value manually seems to fix this.

Closes #1637

1 files changed, 11 insertions, 0 deletions

diff --git a/test/ng/directive/ngClassSpec.js b/test/ng/directive/ngClassSpec.js
index 4a53030b..69afef7a 100644
--- a/test/ng/directive/ngClassSpec.js
+++ b/test/ng/directive/ngClassSpec.js
@@ -236,6 +236,17 @@ describe('ngClass', function() {
   }));
 
 
+  it('should not mess up class value due to observing an interpolated class attribute', inject(function($rootScope, $compile) {
+    $rootScope.foo = true;
+    $rootScope.$watch("anything", function() {
+      $rootScope.foo = false;
+    });
+    element = $compile('<div ng-class="{foo:foo}"></div>')($rootScope);
+    $rootScope.$digest();
+    expect(element.hasClass('foo')).toBe(false);
+  }));
+
+
   it('should update ngClassOdd/Even when model is changed by filtering', inject(function($rootScope, $compile) {
     element = $compile('<ul>' +
       '<li ng-repeat="i in items" ' +