Added test for attachBody

This is just a basic test that ensures that the dropdown is appended to
the end of the dropdown parent when `dropdownParent` is defined.

tests/dropdown/positioning-tests.js

@@ -0,0 +1,59 @@
+module('Dropdown - attachBody - positioning');
+
+test('appends to the dropdown parent', function (assert) {
+    expect(4);
+
+    var $ = require('jquery');
+
+    var $select = $('<select></select>');
+    var $parent = $('<div></div>');
+
+    var $container = $('<span></span>');
+    var container = new MockContainer();
+
+    $parent.appendTo($('#qunit-fixture'));
+    $select.appendTo($parent);
+
+    var Utils = require('select2/utils');
+    var Options = require('select2/options');
+
+    var Dropdown = require('select2/dropdown');
+    var AttachBody = require('select2/dropdown/attachBody');
+
+    var DropdownAdapter = Utils.Decorate(Dropdown, AttachBody);
+
+    var dropdown = new DropdownAdapter($select, new Options({
+        dropdownParent: $parent
+    }));
+
+    assert.equal(
+        $parent.children().length,
+        1,
+        'Only the select should be in the container'
+    );
+
+    var $dropdown = dropdown.render();
+
+    dropdown.bind(container, $container);
+
+    dropdown.position($dropdown, $container);
+
+    assert.equal(
+        $parent.children().length,
+        1,
+        'The dropdown should not be placed until after it is opened'
+    );
+
+    dropdown._showDropdown();
+
+    assert.equal(
+        $parent.children().length,
+        2,
+        'The dropdown should now be in the container as well'
+    );
+
+    assert.ok(
+        $.contains($parent[0], $dropdown[0]),
+        'The dropdown should be contained within the parent container'
+    );
+});

tests/unit.html

@@ -69,6 +69,7 @@
     <script src="data/minimumInputLength-tests.js" type="text/javascript"></script>
 
     <script src="dropdown/dropdownCss-tests.js" type="text/javascript"></script>
+    <script src="dropdown/positioning-tests.js" type="text/javascript"></script>
     <script src="dropdown/selectOnClose-tests.js" type="text/javascript"></script>
     <script src="dropdown/stopPropagation-tests.js" type="text/javascript"></script>