private MPart createPart(MPartDescriptor descriptor) {
   if (descriptor == null) {
     return null;
   }
   MPart part = modelService.createModelElement(MPart.class);
   part.setElementId(descriptor.getElementId());
   part.getMenus().addAll(EcoreUtil.copyAll(descriptor.getMenus()));
   if (descriptor.getToolbar() != null) {
     part.setToolbar((MToolBar) EcoreUtil.copy((EObject) descriptor.getToolbar()));
   }
   part.setContributorURI(descriptor.getContributorURI());
   part.setCloseable(descriptor.isCloseable());
   part.setContributionURI(descriptor.getContributionURI());
   part.setLabel(descriptor.getLabel());
   part.setIconURI(descriptor.getIconURI());
   part.setTooltip(descriptor.getTooltip());
   part.getHandlers().addAll(EcoreUtil.copyAll(descriptor.getHandlers()));
   part.getTags().addAll(descriptor.getTags());
   part.getPersistedState().putAll(descriptor.getPersistedState());
   part.getBindingContexts().addAll(descriptor.getBindingContexts());
   return part;
 }
  @Before
  public void setUp() throws Exception {
    appContext = E4Application.createDefaultContext();
    appContext.set(E4Workbench.PRESENTATION_URI_ARG, PartRenderingEngine.engineURI);

    ems = appContext.get(EModelService.class);

    window = ems.createModelElement(MWindow.class);
    window.setWidth(500);
    window.setHeight(500);

    MPartSashContainer sash = ems.createModelElement(MPartSashContainer.class);
    window.getChildren().add(sash);
    window.setSelectedElement(sash);

    MPartStack stack = ems.createModelElement(MPartStack.class);
    sash.getChildren().add(stack);
    sash.setSelectedElement(stack);

    part = ems.createModelElement(MPart.class);
    part.setElementId("Part");
    part.setLabel("Part");
    part.setToolbar(ems.createModelElement(MToolBar.class));
    part.setContributionURI(Activator.asURI(PartBackend.class));
    stack.getChildren().add(part);

    toolControl = ems.createModelElement(MToolControl.class);
    toolControl.setElementId("ToolControl");
    toolControl.setContributionURI(Activator.asURI(TextField.class));
    part.getToolbar().getChildren().add(toolControl);

    stack = ems.createModelElement(MPartStack.class);
    sash.getChildren().add(stack);
    sash.setSelectedElement(stack);

    otherPart = ems.createModelElement(MPart.class);
    otherPart.setElementId("OtherPart");
    otherPart.setLabel("OtherPart");
    otherPart.setContributionURI(Activator.asURI(PartBackend.class));
    stack.getChildren().add(otherPart);

    MApplication application = ems.createModelElement(MApplication.class);
    application.getChildren().add(window);
    application.setContext(appContext);
    appContext.set(MApplication.class, application);

    wb = new E4Workbench(application, appContext);
    wb.createAndRunUI(window);

    eps = window.getContext().get(EPartService.class);
    // ensure the parts are populated and the contributions instantiated
    eps.activate(part);
    eps.activate(otherPart);
    processEvents();

    // ensure our model backend objects are created
    assertNotNull(part.getObject());
    assertNotNull(toolControl.getObject());
    assertNotNull(otherPart.getObject());

    assertNotNull(part.getWidget());
    assertNotNull(toolControl.getWidget());
    assertNotNull(otherPart.getWidget());

    // ensure focus is set to otherPart.text1
    eps.activate(otherPart);
    processEvents();
    assertTrue(((PartBackend) otherPart.getObject()).text1.isFocusControl());
  }