@Test
 public void testSimpleDefinitionsUnmarshalling() throws Exception {
   Bpmn2JsonUnmarshaller unmarshaller = new Bpmn2JsonUnmarshaller();
   Definitions definitions =
       ((Definitions)
           unmarshaller.unmarshall(getTestJsonFile("empty.json"), "").getContents().get(0));
   assertEquals("my doc", definitions.getDocumentation().iterator().next().getText());
   assertEquals("http://www.w3.org/1999/XPath", definitions.getExpressionLanguage());
   assertEquals("http://www.omg.org/bpmn20", definitions.getTargetNamespace());
   assertEquals("http://www.w3.org/2001/XMLSchema", definitions.getTypeLanguage());
   assertTrue(definitions.getRootElements().isEmpty());
   definitions.eResource().save(System.out, Collections.emptyMap());
 }