Add focus-on-open test coverage

tests/selection/focusing-tests.js

@@ -2,11 +2,47 @@ module('Selection containers - Managing focus');
 
 var SingleSelection = require('select2/selection/single');
 
+var Dropdown = require('select2/dropdown');
+var DropdownSearch = Utils.Decorate(
+  Dropdown,
+  require('select2/dropdown/search')
+);
+
 var $ = require('jquery');
 var Options = require('select2/options');
 
 var options = new Options({});
 
+test('open sets the focus to the search control', function (assert) {
+  var $container = $('#qunit-fixture .event-container');
+  var container = new MockContainer();
+  var selection = new DropdownSearch(
+    $('#qunit-fixture .single'),
+    options
+  );
+
+  var $selection = selection.render();
+  selection.bind(container, $container);
+
+  $container.append($selection);
+
+  var $search = $selection.find('input');
+
+  assert.notEqual(
+    document.activeElement,
+    $search[0],
+    'The selection had focus originally'
+  );
+
+  container.trigger('open');
+
+  assert.equal(
+    document.activeElement,
+    $search[0],
+    'After close, focus must be set to selection'
+  );
+});
+
 test('close sets the focus to the selection', function (assert) {
   var $container = $('#qunit-fixture .event-container');
   var container = new MockContainer();