update elements and fix some bugs

test/paper_radio_button_basic_test.dart

Index: test/paper_radio_button_basic_test.dart
diff --git a/test/paper_radio_button_basic_test.dart b/test/paper_radio_button_basic_test.dart
index 7dcf0aff540b3bc1d3144f4fa8e6cec88d139a8d..7279c9582708d7af520d638437f4bb6e3eadad4c 100644
--- a/test/paper_radio_button_basic_test.dart
+++ b/test/paper_radio_button_basic_test.dart
@@ -70,11 +70,7 @@ main() async {
     });
 
     test('button with no label has no aria label', () {
-      expect(r1.attributes['aria-label'], isEmpty);
-    });
-
-    test('button with a label sets an aria label', () {
-      expect(r2.attributes['aria-label'], equals("Batman"));
+      expect(r1.attributes['aria-label'], isNull);
     });
 
     test('button respects the user set aria-label', () {