Bug 300012 [CommonNavigator] CNF test improvements
Various improvements and corrections.
tests/org.eclipse.ui.tests.navigator/src/org/eclipse/ui/tests/navigator/M12Tests.java
TreeItem[] rootItems = _viewer.getTree().getItems();
		_expand(rootItems);
		TreeItem p2Item = rootItems[_p2Ind];
		TreeItem[] p2Children = p2Item.getItems();
		_expand(p2Children);
		TreeItem file2Child = _findChild("file2.txt", p2Children);
		assertNotNull("P2 should have a child named file2.txt", file2Child);
		assertEquals("file2.txt should be provided by M2 content provider",
				M2File.class, file2Child.getData().getClass());
	}
	/**
	 * Verifies that M1 interceptAdd is called when the resourceContent provider
	 * invokes viewer.add(IResource). As of Galileo, add(IResource) is correctly
	 * pipelined but remove is not.
	 * 
	 * @throws CoreException
	 */
	public void testInterceptAdd() throws CoreException {
		final String NEW_FOLDER_1 = "newFolder1";
		_initContent();
		TreeItem[] rootItems = _viewer.getTree().getItems();
		
		_expand(rootItems);
		IFolder newFolder1 = _p1.getFolder(NEW_FOLDER_1);
		newFolder1.create(true, true, new NullProgressMonitor());
		TreeItem folder1Item = _findChild(NEW_FOLDER_1, rootItems[_p1Ind]
				.getItems());
		assertNotNull("M1 interceptAdd method should have been called",
				folder1Item);
	}