Runs the test case.
Document doc;
NodeList testList;
Node piNode;
String piValue;
doc = (Document) load("staff", true);
testList = doc.getChildNodes();
piNode = testList.item(0);
piNode.setNodeValue("Something different");
piValue = piNode.getNodeValue();
assertEquals("nodeValue", "Something different", piValue);
piValue = ((ProcessingInstruction) /*Node */piNode).getData();
assertEquals("data", "Something different", piValue);