### Question:
NodeDefinitionHelper { public static String getContentDefinitionId(final Node node) { if (node.getContent() instanceof Definition) { final Object definition = ((Definition) node.getContent()).getDefinition(); if (definition instanceof HasContentDefinitionId) { return ((HasContentDefinitionId) definition).getContentDefinitionId(); } } return null; }  static String getDiagramId(final Node node); static String getContentDefinitionId(final Node node);  }### Answer:
@Test public void testGetContentDefinitionId() { final String contentDefinitionId = "contentDefinitionId"; final Node node = createNode(contentDefinitionId, "id"); final String actual = getContentDefinitionId(node); assertEquals(contentDefinitionId, actual); }