processor.handleReturnValue(messageContext, rootElementReturnType, rootElement);
assertTrue("context has no response", messageContext.hasResponse());
AxiomSoapMessage response = (AxiomSoapMessage) messageContext.getResponse();
ByteArrayOutputStream bos = new ByteArrayOutputStream();
response.writeTo(bos);
String messageResult = bos.toString("UTF-8");
assertXMLEqual("<soapenv:Envelope xmlns:soapenv='http://schemas.xmlsoap.org/soap/envelope/'><soapenv:Body>" +
"<root xmlns='http://springframework.org'><string>Foo</string></root>" +
"</soapenv:Body></soapenv:Envelope>", messageResult);