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
MApplication application = ApplicationFactoryImpl.eINSTANCE
				.createApplication();
		MPartDescriptor partDescriptor = org.eclipse.e4.ui.model.application.descriptor.basic.impl.BasicFactoryImpl.eINSTANCE
				.createPartDescriptor();
		partDescriptor.setElementId("partId");
		application.getDescriptors().add(partDescriptor);
		MWindow window = BasicFactoryImpl.eINSTANCE.createWindow();
		application.getChildren().add(window);
		application.setSelectedElement(window);
		MPerspectiveStack perspectiveStack = AdvancedFactoryImpl.eINSTANCE
				.createPerspectiveStack();
		window.getChildren().add(perspectiveStack);
		window.setSelectedElement(perspectiveStack);
		MPerspective perspective = AdvancedFactoryImpl.eINSTANCE
				.createPerspective();
		perspectiveStack.getChildren().add(perspective);
		perspectiveStack.setSelectedElement(perspective);
		MPartSashContainer partSashContainer = BasicFactoryImpl.eINSTANCE
				.createPartSashContainer();
		perspective.getChildren().add(partSashContainer);
		perspective.setSelectedElement(partSashContainer);
		MPart partA = BasicFactoryImpl.eINSTANCE.createPart();
		partSashContainer.getChildren().add(partA);
		partSashContainer.setSelectedElement(partA);
		initialize(applicationContext, application);
		getEngine().createGui(window);
		EPartService partService = window.getContext().get(EPartService.class);
		partService.showPart("partId", PartState.ACTIVATE);
		assertEquals(2, partSashContainer.getChildren().size());
		assertEquals(partA, partSashContainer.getChildren().get(0));