select-kit refactoring

* better test helper
* more reliable tests
* more consistent use of data-value/data-name/title/aria-label everywhere: header and rows

test/javascripts/acceptance/topic-test.js.es6

@@ -48,16 +48,13 @@ QUnit.test("Showing and hiding the edit controls", assert => {
 });
 
 QUnit.test("Updating the topic title and category", assert => {
+  const categoryChooser = selectKit('.title-wrapper .category-chooser');
+
   visit("/t/internationalization-localization/280");
 
   click('#topic-title .d-icon-pencil');
-
   fillIn('#edit-title', 'this is the new title');
-
-  expandSelectKit('.title-wrapper .category-chooser');
-
-  selectKitSelectRow(4, {selector: '.title-wrapper .category-chooser'});
-
+  categoryChooser.expand().selectRowByValue(4);
   click('#topic-title .submit-edit');
 
   andThen(() => {
@@ -104,7 +101,7 @@ QUnit.test("Reply as new topic", assert => {
       "it fills composer with the ring string"
     );
     assert.equal(
-      selectKit('.category-chooser').header.name(), "feature",
+      selectKit('.category-chooser').header().value(), "2",
       "it fills category selector with the right category"
     );
   });