refactor(directives): directives use declare that they listen to onChange in the annotations

modules/angular2/test/core/annotations/annotations_spec.js

@@ -0,0 +1,23 @@
+import {ddescribe, describe, it, iit, expect, beforeEach} from 'angular2/test_lib';
+import {Directive, onChange} from 'angular2/src/core/annotations/annotations';
+
+export function main() {
+  describe("Directive", () => {
+    describe("lifecycle", () => {
+      it("should be false when no lifecycle specified", () => {
+        var d = new Directive();
+        expect(d.hasLifecycleHook(onChange)).toBe(false);
+      });
+
+      it("should be false when the lifecycle does not contain the hook", () => {
+        var d = new Directive({lifecycle:[]});
+        expect(d.hasLifecycleHook(onChange)).toBe(false);
+      });
+
+      it("should be true otherwise", () => {
+        var d = new Directive({lifecycle:[onChange]});
+        expect(d.hasLifecycleHook(onChange)).toBe(true);
+      });
+    });
+  });
+}