fix(input): work with async value bindings

 - add test for async @input() bindings to value.
 - move @input() on to the setter function rather than the internal data member.
 - closes #40, #39, #59

ng2-material/components/input/input.ts

@@ -32,9 +32,9 @@ import {DOM} from "angular2/src/platform/dom/dom_adapter";
   providers: [FORM_PROVIDERS]
 })
 export class MdInput {
-  @Input('value')
   _value: string;
 
+  @Input('value')
   set value(value: string) {
     this._value = value;
     ObservableWrapper.callEmit(this.mdChange, this.value);

test/components/input/input_spec.ts

@@ -1,4 +1,4 @@
-import {componentSanityCheck} from "../../util";
+import {componentSanityCheck, promiseWait} from "../../util";
 import {
   TestComponentBuilder,
   beforeEach,
@@ -9,7 +9,7 @@ import {
   injectAsync,
   ComponentFixture
 } from "angular2/testing";
-import {Component, View, DebugElement} from "angular2/core";
+import {Component, View, DebugElement, Input} from "angular2/core";
 import {MdInput, MdInputContainer} from "../../../ng2-material/components/input/input";
 import {By} from "angular2/platform/browser";
 
@@ -32,6 +32,8 @@ export function main() {
     template: template
   })
   class TestComponent {
+
+    @Input() boundValue;
   }
 
   describe('Input', () => {
@@ -66,6 +68,26 @@ export function main() {
           expect(api.input.value).toBe('');
         });
       }));
+      it('should emit change event when value binding is updated after init', injectAsync([], () => {
+        let tpl = `
+        <md-input-container>
+          <input md-input type="text" [value]="boundValue">
+        </md-input-container>`;
+        return setup(tpl).then((api: IInputFixture) => {
+          let newValue = 'something-great';
+          expect(api.input.value).toBe('');
+          return promiseWait().then(() => {
+            return new Promise((resolve) => {
+              api.input.mdChange.subscribe((changed: string) => {
+                expect(changed).toBe(newValue);
+                resolve();
+              });
+              api.fixture.componentInstance.boundValue = newValue;
+              api.fixture.detectChanges();
+            });
+          });
+        });
+      }));
     });
   });