final List<SessionInfo> sessionInfos,
final Collection<ExecutionData> executionData) throws IOException {
if (output == null) {
throw new IllegalStateException("No report output set.");
}
final ReportOutputFolder root = new ReportOutputFolder(output);
resources = new Resources(root);
resources.copyResources();
index = new ElementIndex(root);
final GroupPage rootpage = new GroupPage(rootNode, null, root, this) {
@Override