protected NormalFlowRA getFirstNormalFlowArea(final AreaTree areaTree) {
final PageCollection pageCollection = getPageCollection(areaTree, 1);
final PageRA firstPage = getPage(pageCollection, 1);
final RegionRABody regionBody = firstPage.getRegionBody(
"xsl-region-body");
final MainRA main = regionBody.getMainRefArea();
AreaNode node = main.getChildAt(0);
assertTrue(node instanceof SpanRA);
final SpanRA span = (SpanRA) node;
node = span.getChildAt(0);
assertTrue(node instanceof NormalFlowRA);
final NormalFlowRA nfa = (NormalFlowRA) node;