add tests

Author: mmalerba

src/lib/datepicker/datepicker-input.ts

@@ -58,7 +58,7 @@ export const MD_DATEPICKER_VALIDATORS: any = {
   providers: [MD_DATEPICKER_VALUE_ACCESSOR, MD_DATEPICKER_VALIDATORS],
   host: {
     '[attr.aria-haspopup]': 'true',
-    '[attr.aria-owns]': '_datepicker?.opened && _datepicker.id',
+    '[attr.aria-owns]': '(_datepicker?.opened && _datepicker.id) || null',
     '[attr.min]': 'min ? _dateAdapter.getISODateString(min) : null',
     '[attr.max]': 'max ? _dateAdapter.getISODateString(max) : null',
     '[disabled]': 'disabled',

src/lib/datepicker/datepicker.spec.ts

@@ -189,6 +189,39 @@ describe('MdDatepicker', () => {
         expect(attachToRef.nativeElement.tagName.toLowerCase())
             .toBe('input', 'popup should be attached to native input');
       });
+
+      it('input should aria-owns calendar after opened in non-touch mode', () => {
+        let inputEl = fixture.debugElement.query(By.css('input')).nativeElement;
+        expect(inputEl.getAttribute('aria-owns')).toBeNull();
+
+        testComponent.datepicker.open();
+        fixture.detectChanges();
+
+        let ownedElementId = inputEl.getAttribute('aria-owns');
+        expect(ownedElementId).not.toBeNull();
+
+        let ownedElement = document.getElementById(ownedElementId);
+        expect(ownedElement).not.toBeNull();
+        expect((ownedElement as Element).tagName.toLowerCase()).toBe('md-calendar');
+      });
+
+      it('input should aria-owns calendar after opened in touch mode', () => {
+        testComponent.touch = true;
+        fixture.detectChanges();
+
+        let inputEl = fixture.debugElement.query(By.css('input')).nativeElement;
+        expect(inputEl.getAttribute('aria-owns')).toBeNull();
+
+        testComponent.datepicker.open();
+        fixture.detectChanges();
+
+        let ownedElementId = inputEl.getAttribute('aria-owns');
+        expect(ownedElementId).not.toBeNull();
+
+        let ownedElement = document.getElementById(ownedElementId);
+        expect(ownedElement).not.toBeNull();
+        expect((ownedElement as Element).tagName.toLowerCase()).toBe('md-calendar');
+      });
     });
 
     describe('datepicker with too many inputs', () => {