Bug 334559 EPartService's part searching path may not include parts outside of the active perspective
tests/org.eclipse.e4.ui.tests/src/org/eclipse/e4/ui/tests/application/EPartServiceTest.java
partDescriptor.setElementId("partId"); 
		application.getDescriptors().add(partDescriptor);
		MWindow window = BasicFactoryImpl.eINSTANCE.createWindow();
		application.getChildren().add(window);
		application.setSelectedElement(window);
		MPart partA = BasicFactoryImpl.eINSTANCE.createPart();
		partA.setElementId("partId"); 
		window.getSharedElements().add(partA);
		MPerspectiveStack perspectiveStack = AdvancedFactoryImpl.eINSTANCE
				.createPerspectiveStack();
		window.getChildren().add(perspectiveStack);
		window.setSelectedElement(perspectiveStack);
		MPerspective perspectiveA = AdvancedFactoryImpl.eINSTANCE
				.createPerspective();
		perspectiveStack.getChildren().add(perspectiveA);
		perspectiveStack.setSelectedElement(perspectiveA);
		initialize(applicationContext, application);
		getEngine().createGui(window);
		EPartService partService = perspectiveA.getContext().get(
				EPartService.class);
		partService.showPart(partA, PartState.ACTIVATE);
		assertNotNull(partA.getCurSharedRef());
	}
	public void testShowPart_Bug320578_B() {
		MApplication application = ApplicationFactoryImpl.eINSTANCE
				.createApplication();
		MWindow window = BasicFactoryImpl.eINSTANCE.createWindow();
		application.getChildren().add(window);
		application.setSelectedElement(window);
		MPart partA = BasicFactoryImpl.eINSTANCE.createPart();