问AngularJS -将函数传递给指令

EN

<div ng-controller="testCtrl">

<test color1="color1" updateFn="updateFn()"></test>
</div>
 <script>
  angular.module('dr', [])
.controller("testCtrl", function($scope) {
    $scope.color1 = "color";
    $scope.updateFn = function() {
        alert('123');
    }
})
.directive('test', function() {
    return {
        restrict: 'E',
        scope: {color1: '=',
                updateFn: '&'},
        template: "<button ng-click='updateFn()'>Click</button>",
        replace: true,
        link: function(scope, elm, attrs) { 
        }
    }
});

</script>
</body>

</html>