Runs the test case.
Document doc;
NodeList elementList;
Node employeeNode;
Node fcNode;
Node psNode;
doc = (Document) load("hc_staff", false);
elementList = doc.getElementsByTagName("p");
employeeNode = elementList.item(2);
fcNode = employeeNode.getFirstChild();
psNode = fcNode.getPreviousSibling();
assertNull("nodeGetPreviousSiblingNullAssert1", psNode);