final Application application = new Application("test", "Test", new EmptySession(), new ApplicationManagerOption());
final UIContext uiContext = new UIContext(application);
UIContext.setCurrent(uiContext);
txn = Txn.get();
txn.begin(new EmptyTxnContext());
PPusher.initialize();
final RefreshableDataGridColumnDescriptor<Data, Data, PHTML> descriptor = new RefreshableDataGridColumnDescriptor<Data, Data, PHTML>();
descriptor.setValueProvider(new IdentityValueProvider<Data>());
descriptor.setHeaderCellRenderer(new HeaderCellRenderer() {