feat(alert): allow alerts to be closed from a controller

Closes #2399
Closes #2854

src/alert/alert.js

@@ -2,6 +2,7 @@ angular.module('ui.bootstrap.alert', [])
 
 .controller('AlertController', ['$scope', '$attrs', function ($scope, $attrs) {
   $scope.closeable = 'close' in $attrs;
+  this.close = $scope.close;
 }])
 
 .directive('alert', function () {
@@ -16,4 +17,15 @@ angular.module('ui.bootstrap.alert', [])
       close: '&'
     }
   };
-});
+})
+
+.directive('dismissOnTimeout', ['$timeout', function($timeout) {
+  return {
+    require: 'alert',
+    link: function(scope, element, attrs, alertCtrl) {
+      $timeout(function(){
+        alertCtrl.close();
+      }, parseInt(attrs.dismissOnTimeout, 10));
+    }
+  };
+}]);

src/alert/test/dismissOnTimeout.spec.js

@@ -0,0 +1,21 @@
+describe('dismissOnTimeout', function () {
+
+  var scope, $compile, $timeout;
+
+  beforeEach(module('ui.bootstrap.alert'));
+  beforeEach(module('template/alert/alert.html'));
+  beforeEach(inject(function ($rootScope, _$compile_, _$timeout_) {
+    scope = $rootScope;
+    $compile = _$compile_;
+    $timeout = _$timeout_;
+  }));
+
+  it('should close automatically if auto-dismiss is defined on the element', function () {
+    scope.removeAlert = jasmine.createSpy();
+    $compile('<alert close="removeAlert()" dismiss-on-timeout="500">Default alert!</alert>')(scope);
+    scope.$digest();
+
+    $timeout.flush();
+    expect(scope.removeAlert).toHaveBeenCalled();
+  });
+});