fix(select): multiselect failes to update view on selection insert

In multiselect when the underlying selection array push/pops an element the view did not re-render since the array reference stayed the same.

Author: mhevery

src/directive/select.js

@@ -174,13 +174,23 @@ var selectDirective = ['$compile', '$parse', function($compile,   $parse) {
       }
 
       function Multiple(scope, selectElement, ctrl) {
+        var lastView;
         ctrl.$render = function() {
           var items = new HashMap(ctrl.$viewValue);
           forEach(selectElement.children(), function(option) {
             option.selected = isDefined(items.get(option.value));
           });
         };
 
+        // we have to do it on each watch since ng-model watches reference, but
+        // we need to work of an array, so we need to see if anything was inserted/removed
+        scope.$watch(function() {
+          if (!equals(lastView, ctrl.$viewValue)) {
+            lastView = copy(ctrl.$viewValue);
+            ctrl.$render();
+          }
+        });
+
         selectElement.bind('change', function() {
           scope.$apply(function() {
             var array = [];

test/directive/selectSpec.js

@@ -102,7 +102,15 @@ describe('select', function() {
         scope.selection = ['A'];
       });
 
-      expect(element[0].childNodes[0].selected).toEqual(true);
+      expect(element.find('option')[0].selected).toEqual(true);
+      expect(element.find('option')[1].selected).toEqual(false);
+
+      scope.$apply(function() {
+        scope.selection.push('B');
+      });
+
+      expect(element.find('option')[0].selected).toEqual(true);
+      expect(element.find('option')[1].selected).toEqual(true);
     });