fixed group ripple disabled test

Author: tinayuangao

src/lib/radio/radio.spec.ts

@@ -242,7 +242,7 @@ describe('MdRadio', () => {
       let rippleElement = radioNativeElements[0].querySelector('[md-ripple]');
       expect(rippleElement).toBeTruthy('Expected an enabled radio button to have a ripple');
 
-      radioInstances[0].disabled = true;
+      testComponent.isFirstDisabled = true;
       fixture.detectChanges();
 
       rippleElement = radioNativeElements[0].querySelector('[md-ripple]');
@@ -591,7 +591,8 @@ describe('MdRadio', () => {
                   [labelPosition]="labelPos"
                   [value]="groupValue"
                   name="test-name">
-    <md-radio-button value="fire" [disableRipple]="disableRipple">Charmander</md-radio-button>
+    <md-radio-button value="fire" [disableRipple]="disableRipple"
+                     [disabled]="isFirstDisabled">Charmander</md-radio-button>
     <md-radio-button value="water" [disableRipple]="disableRipple">Squirtle</md-radio-button>
     <md-radio-button value="leaf" [disableRipple]="disableRipple">Bulbasaur</md-radio-button>
   </md-radio-group>
@@ -600,6 +601,7 @@ describe('MdRadio', () => {
 class RadiosInsideRadioGroup {
   labelPos: 'before' | 'after';
   isGroupDisabled: boolean = false;
+  isFirstDisabled: boolean = false;
   groupValue: string = null;
   disableRipple: boolean = false;
 }

src/lib/radio/radio.ts

@@ -139,7 +139,7 @@ export class MdRadioGroup implements AfterContentInit, ControlValueAccessor {
   set labelPosition(v) {
     this._labelPosition = (v == 'before') ? 'before' : 'after';
     if (this._radios) {
-      this._radios.forEach(radio => radio.groupValueChanged());
+      this._radios.forEach(radio => radio._groupValueChanged());
     }
   }
 
@@ -150,7 +150,7 @@ export class MdRadioGroup implements AfterContentInit, ControlValueAccessor {
     // The presence of *any* disabled value makes the component disabled, *except* for false.
     this._disabled = (value != null && value !== false) ? true : null;
     if (this._radios) {
-      this._radios.forEach(radio => radio.groupValueChanged());
+      this._radios.forEach(radio => radio._groupValueChanged());
     }
   }
 
@@ -446,7 +446,7 @@ export class MdRadioButton implements OnInit {
     this._disabled = (value != null && value !== false) ? true : null;
   }
 
-  groupValueChanged() {
+  _groupValueChanged() {
     this._changeDetector.markForCheck();
   }