Test year selection for date picker

packages/unit/test/widget/date_picker_test.dart

@@ -27,8 +27,16 @@ void main() {
     tester.pumpFrame(builder);
 
     expect(currentValue, isNull);
+    tester.tap(tester.findText('2015'));
+    tester.pumpFrame(builder);
+    // TODO(jackson): We shouldn't need to pump a second frame here.
+    tester.pumpFrame(builder);
+    tester.tap(tester.findText('2014'));
+    tester.pumpFrame(builder);
+    // TODO(jackson): We shouldn't need to pump a second frame here.
+    tester.pumpFrame(builder);
+    expect(currentValue, equals(new DateTime(2014, 6, 9)));
     tester.tap(tester.findText('30'));
     expect(currentValue, equals(new DateTime(2013, 1, 30)));
-
   });
 }