Bug 303218 Active part no longer seems to be queryable from the application's context
tests/org.eclipse.e4.ui.tests/src/org/eclipse/e4/ui/tests/application/EPartServiceTest.java
for (MPart partA : partsA) {
			assertFalse(partsB.contains(partA));
		}
	}
	public void testIsPartVisible_NotInStack(boolean selected, boolean visible) {
		MApplication application = MApplicationFactory.eINSTANCE
				.createApplication();
		MWindow window = MApplicationFactory.eINSTANCE.createWindow();
		application.getChildren().add(window);
		application.setSelectedElement(window);
		MPart part = MApplicationFactory.eINSTANCE.createPart();
		part.setVisible(visible);
		window.getChildren().add(part);
		if (selected) {
			window.setSelectedElement(part);
		}
		initialize(applicationContext, application);
		getEngine().createGui(window);
		EPartService partService = (EPartService) window.getContext().get(
				EPartService.class.getName());
		assertEquals(visible, partService.isPartVisible(part));
		partService = (EPartService) part.getContext().get(
				EPartService.class.getName());
		assertEquals(visible, partService.isPartVisible(part));
	}
	public void testIsPartVisible_NotInStackTrueTrue() {
		testIsPartVisible_NotInStack(true, true);
	}
	public void testIsPartVisible_NotInStackTrueFalse() {
		testIsPartVisible_NotInStack(true, false);