engine.compare(control, control, listener);
engine.compare(control, control, listener, null);
    public void testCompareNode() throws Exception {        Document controlDocument = XMLUnit.buildControlDocument("<root>"            + "<!-- " + COMMENT_A + " -->"            + "<?" + PROC_A[0] + " "+ PROC_A[1] + " ?>"            + "<elem attr=\"" + ATTR_A + "\">" + TEXT_A + "</elem></root>");        Document testDocument = XMLUnit.buildTestDocument("<root>"            + "<!-- " + COMMENT_B + " -->"            + "<?" + PROC_B[0] + " "+ PROC_B[1] + " ?>"            + "<elem attr=\"" + ATTR_B + "\">" + TEXT_B + "</elem></root>");        engine.compare(controlDocument, testDocument, listener);        Node control = controlDocument.getDocumentElement().getFirstChild();        Node test = testDocument.getDocumentElement().getFirstChild();        do {            resetListener();            engine.compare(control, test, listener);            assertEquals(true, -1 != listener.comparingWhat);            assertEquals(false, listener.nodesSkipped);            resetListener();            engine.compare(control, control, listener);            assertEquals(-1, listener.comparingWhat);            control = control.getNextSibling();            test = test.getNextSibling();        } while (control != null);    }