fix(select): remove selection if option is removed (#2560)

* fix(select): remove selection if option is removed

* Currenty when an option is selected and the option is somehow programmatically removed the select updates its options.
  Right now it does not remove the selection if the selection has been removed from the options.

Fixes #2524

* Update spec name

* Remove check logic and just keep test

* Update expectation message

* Fix linting

* Wait for zone to be stable

Author: devversion

src/lib/select/select.spec.ts

@@ -180,6 +180,28 @@ describe('MdSelect', () => {
       expect(optionInstances[2].selected).toBe(false);
     });
 
+    it('should remove selection if option has been removed', async(() => {
+      let select = fixture.componentInstance.select;
+
+      trigger.click();
+      fixture.detectChanges();
+
+      let firstOption = overlayContainerElement.querySelectorAll('md-option')[0] as HTMLElement;
+
+      firstOption.click();
+      fixture.detectChanges();
+
+      expect(select.selected).toBe(select.options.first, 'Expected first option to be selected.');
+
+      fixture.componentInstance.foods = [];
+      fixture.detectChanges();
+
+      fixture.whenStable().then(() => {
+        expect(select.selected)
+          .toBe(null, 'Expected selection to be removed when option no longer exists.');
+      });
+    }));
+
     it('should display the selected option in the trigger', () => {
       trigger.click();
       fixture.detectChanges();