### Question:
DocumentFactory { public static Transformer createTransformer() throws TransformerConfigurationException { return getTransformerFactory().newTransformer(); } private  DocumentFactory(); static Document createDocument(); static Document createDocument(InputStream input); static Transformer createTransformer();  }### Answer:
@Test void testCreateTransformer() throws TransformerConfigurationException { assertNotNull(DocumentFactory.createTransformer()); assertNotNull(DocumentFactory.createTransformer()); }