@Test
    public void can_set_and_get_concrete_reference_document_id() {
        final Book book = getBook();
        final DocumentId docId = new DocumentId("id:ns:parent::foo");
        book.setRef(docId); // TODO currently no validation of ID upon setRef time
        assertEquals(docId, book.getRef());
    }
Tests vespa-documentgen-plugin

@author vegardh
documentgen-test/src/test/java/com/yahoo/vespa/config/DocumentGenPluginTest.java