public function testExtensionAttributes() {
     $extensionAttributes = $this->accessLevel->extensionAttributes;
     $extensionAttributes['foo1'] = array('name'=>'foo1', 'value'=>'bar');
     $extensionAttributes['foo2'] = array('name'=>'foo2', 'value'=>'rab');
     $this->accessLevel->extensionAttributes = $extensionAttributes;
     $this->assertEquals('bar', $this->accessLevel->extensionAttributes['foo1']['value']);
     $this->assertEquals('rab', $this->accessLevel->extensionAttributes['foo2']['value']);
     $accessLevelXml = $this->accessLevel->saveXML();
     $newAccessLevel = new Extension\AccessLevel();
     $newAccessLevel->transferFromXML($accessLevelXml);
     $this->assertEquals('bar', $newAccessLevel->extensionAttributes['foo1']['value']);
     $this->assertEquals('rab', $newAccessLevel->extensionAttributes['foo2']['value']);
 }