Bug 262707 [CommonNavigator] CommonViewerSorter gets NPE when misconfigured
tests/org.eclipse.ui.tests.navigator/src/org/eclipse/ui/tests/navigator/NavigatorTestBase.java
public static final String TEST_CONTENT2 = "org.eclipse.ui.tests.navigator.testOverriddenContent2";
	public static final String TEST_OVERRIDE1= "org.eclipse.ui.tests.navigator.testOverride1";
	public static final String TEST_OVERRIDE2 = "org.eclipse.ui.tests.navigator.testOverride2";
	protected String _navigatorInstanceId;
	protected Set expectedChildren = new HashSet();
	protected IProject project;
	protected CommonViewer viewer;
	protected CommonNavigator _commonNavigator;
	protected INavigatorContentService contentService;
	protected NavigatorActionService _actionService;
	protected boolean _initTestData = true;
	protected void setUp() throws Exception {
		if (_navigatorInstanceId == null) {
			throw new RuntimeException(
					"Set the _navigatorInstanceId in the constructor");
		}
		if (_initTestData) {
			TestWorkspace.init();
			IWorkspaceRoot root = ResourcesPlugin.getWorkspace().getRoot();
			project = root.getProject("Test"); 
			expectedChildren.add(project.getFolder("src")); 
			expectedChildren.add(project.getFolder("bin")); 
			expectedChildren.add(project.getFile(".project")); 
			expectedChildren.add(project.getFile(".classpath"));  
			expectedChildren.add(project.getFile("model.properties")); 
		}
		EditorTestHelper.showView(_navigatorInstanceId, true);
		IWorkbenchWindow activeWindow = PlatformUI.getWorkbench()
				.getActiveWorkbenchWindow();
		IWorkbenchPage activePage = activeWindow.getActivePage();