Test administrative users other than user 1 can access the menu parents AJAX callback.
public function testMenuParentsJsAccess() {
$admin = $this
->drupalCreateUser(array(
'administer menu',
));
$this
->drupalLogin($admin);
// Just check access to the callback overall, the POST data is irrelevant.
$this
->drupalGetAJAX('admin/structure/menu/parents');
$this
->assertResponse(200);
// Do standard user tests.
// Login the user.
$this
->drupalLogin($this->std_user);
$this
->drupalGetAJAX('admin/structure/menu/parents');
$this
->assertResponse(403);
}