public function testValidLocalReference()
 {
     /** @var File $exampleFile */
     $exampleFile = $this->objFromFixture('SilverStripe\\Assets\\File', 'example_file');
     $expectedUrl = $exampleFile->AbsoluteLink();
     HTMLEditorField_Toolbar::config()->update('fileurl_domain_whitelist', array('example.com', strtolower(parse_url($expectedUrl, PHP_URL_HOST))));
     list($file, $url) = $this->getToolbar()->viewfile_getRemoteFileByURL($exampleFile->AbsoluteLink());
     $this->assertEquals($expectedUrl, $url);
 }