Ajax testing - JUnit in Action - page 248

we do is a simple string comparison of the start of the document G . You could also
use Java regular expressions to do some further XML string-based checks; next, we use
an important XML feature: XML validation.

13.7.2 Validating an XML response

If you can parse an XML document, you know that it's well formed, meaning that the
XML syntax is obeyed, nothing more. XML provides a standard called XML Schema,
which you use to define a vocabulary of XML , specifying which elements and attributes
make up a valid document. In this next example, the schema is stored in a file called
personal.xsd. Listing 13.11 uses the standard Java XML API s to validate the XML docu-
ment returned from a server call against an XML Schema.

Listing 13.11 A validating XML service test

@Test
public void testGetXmlAndValidateXmlSchema() throws
IOException, ParserConfigurationException, SAXException {
HttpClient httpClient = new HttpClient();
GetMethod get = new GetMethod(
" http://localhost/ch13personal/personal.xml");
Document document;
try {
httpClient.executeMethod(get);
InputStream input = get.getResponseBodyAsStream();
// Parse the XML document into a DOM tree
DocumentBuilder parser = DocumentBuilderFactory
.newInstance().newDocumentBuilder();
document = parser.parse(input);
} finally {
get.releaseConnection();
}

B

// Create a SchemaFactory capable of understanding XSD schemas
SchemaFactory factory = SchemaFactory.newInstance(
XMLConstants.W3C_XML_SCHEMA_NS_URI);

C

// Load the XSD schema in a Schema instance
Source schemaFile = new StreamSource(new File(
"src/main/webapp/personal.xsd"));
Schema schema = factory.newSchema(schemaFile);

D

// Create a Validator, which we use to validate the document
Validator validator = schema.newValidator();
validator.validate(new DOMSource(document));
}
This example starts as the previous one did, but after the test executes the HTTP GET
method, we read the server response directly with an XML parser b . If the DOM docu-
ment parses successfully, we know the document is well formed, a nice sanity check. If
we don't get a valid XML document from the server, we might have a server error mes-
sage in the response or a bug in server-side XML document generation. We can now
move to the meat of the test, XML validation. We create a schema factory for the kind

E