Bug 329310 Part service does not autogenerate stacks if the last container is not one
tests/org.eclipse.e4.ui.tests/src/org/eclipse/e4/ui/tests/application/EPartServiceTest.java
window.setSelectedElement(perspectiveStack);
		MPerspective perspective = AdvancedFactoryImpl.eINSTANCE
				.createPerspective();
		perspectiveStack.getChildren().add(perspective);
		perspectiveStack.setSelectedElement(perspective);
		MPartStack partStack = BasicFactoryImpl.eINSTANCE.createPartStack();
		perspective.getChildren().add(partStack);
		perspective.setSelectedElement(partStack);
		MPart partA = BasicFactoryImpl.eINSTANCE.createPart();
		partStack.getChildren().add(partA);
		partStack.setSelectedElement(partA);
		MPlaceholder placeholderB = AdvancedFactoryImpl.eINSTANCE
				.createPlaceholder();
		partB.setCurSharedRef(placeholderB);
		placeholderB.setRef(partB);
		partStack.getChildren().add(placeholderB);
		initialize(applicationContext, application);
		getEngine().createGui(window);
		EPartService partService = (EPartService) window.getContext().get(
				EPartService.class.getName());
		partService.activate(partA);
		assertEquals(partA, partService.getActivePart());
		partService.bringToTop(partB);
		assertEquals(partB, partService.getActivePart());
	}
	public void testBringToTop_Unrendered() {
		MApplication application = createApplication("partFront", "partBack");
		MWindow window = application.getChildren().get(0);
		MPartStack partStack = (MPartStack) window.getChildren().get(0);
		MPart partFront = (MPart) partStack.getChildren().get(0);