test(matchers): add support for toHaveClass in tests

modules/angular2/src/test_lib/test_lib.dart

@@ -100,6 +100,7 @@ class Expect extends gns.Expect {
   void toThrowError([message = ""]) => toThrowWith(message: message);
   void toThrowErrorWith(message) => expectException(this.actual, message);
   void toBePromise() => gns.guinness.matchers.toBeTrue(actual is Future);
+  void toHaveCssClass(className) => gns.guinness.matchers.toBeTrue(DOM.hasClass(actual, className));
   void toImplement(expected) => toBeA(expected);
   void toBeNaN() =>
       gns.guinness.matchers.toBeTrue(double.NAN.compareTo(actual) == 0);
@@ -138,6 +139,7 @@ class NotExpect extends gns.NotExpect {
 
   void toEqual(expected) => toHaveSameProps(expected);
   void toBePromise() => gns.guinness.matchers.toBeFalse(actual is Future);
+  void toHaveCssClass(className) => gns.guinness.matchers.toBeFalse(DOM.hasClass(actual, className));
   void toBeNull() => gns.guinness.matchers.toBeFalse(actual == null);
   Function get _expect => gns.guinness.matchers.expect;
 }

modules/angular2/src/test_lib/test_lib.ts

@@ -24,6 +24,7 @@ export interface NgMatchers extends jasmine.Matchers {
   toBePromise(): boolean;
   toBeAnInstanceOf(expected: any): boolean;
   toHaveText(expected: any): boolean;
+  toHaveCssClass(expected: any): boolean;
   toImplement(expected: any): boolean;
   toContainError(expected: any): boolean;
   toThrowErrorWith(expectedMessage: any): boolean;
@@ -244,6 +245,21 @@ _global.beforeEach(function() {
       };
     },
 
+    toHaveCssClass: function() {
+      return {compare: buildError(false), negativeCompare: buildError(true)};
+
+      function buildError(isNot) {
+        return function(actual, className) {
+          return {
+            pass: DOM.hasClass(actual, className) == !isNot,
+            get message() {
+              return `Expected ${actual.outerHTML} ${isNot ? 'not ' : ''}to contain the CSS class "${className}"`;
+            }
+          };
+        };
+      }
+    },
+
     toContainError: function() {
       return {
         compare: function(actual, expectedText) {

modules/angular2/test/test_lib/test_lib_spec.ts

@@ -11,6 +11,7 @@ import {
   containsRegexp
 } from 'angular2/test_lib';
 
+import {DOM} from 'angular2/src/dom/dom_adapter';
 import {MapWrapper} from 'angular2/src/facade/collection';
 import {IMPLEMENTS, RegExpWrapper} from 'angular2/src/facade/lang';
 
@@ -42,6 +43,20 @@ export function main() {
       });
     });
 
+    describe("toHaveCssClass", () => {
+      it("should assert that the CSS class is present", () => {
+        var el = DOM.createElement('div');
+        DOM.addClass(el, 'matias');
+        expect(el).toHaveCssClass('matias');
+      });
+
+      it("should assert that the CSS class is not present", () => {
+        var el = DOM.createElement('div');
+        DOM.addClass(el, 'matias');
+        expect(el).not.toHaveCssClass('fatias');
+      });
+    });
+
     describe('toEqual for Maps', () => {
       it('should detect equality for same reference', () => {
         var m1 = MapWrapper.createFromStringMap({'a': 1});