public function testListVocabularies()
 {
     MwRdf::registerVocabulary("rdf", "MwRdf_Vocabulary_Rdf");
     MwRdf::registerVocabulary("rdfs", "MwRdf_Vocabulary_RdfSchema");
     MwRdf::registerVocabulary("cc", "MwRdf_Vocabulary_CreativeCommons");
     MwRdf::registerVocabulary("dc", "MwRdf_Vocabulary_DCMES");
     $this->assertType('array', MwRdf::ListVocabularies());
     $this->assertContains('rdf', MwRdf::ListVocabularies());
     $this->assertContains('rdfs', MwRdf::ListVocabularies());
     $this->assertContains('cc', MwRdf::ListVocabularies());
     $this->assertContains('dc', MwRdf::ListVocabularies());
 }