Runs the test case.
Document doc;
NodeList elementList;
Element testEmployee;
Attr domesticAttr;
doc = (Document) load("hc_staff", true);
elementList = doc.getElementsByTagName("acronym");
testEmployee = (Element) elementList.item(0);
domesticAttr = testEmployee.getAttributeNode("invalidAttribute");
assertNull("elementGetAttributeNodeNullAssert", domesticAttr);