Rebase issue resolution.

src/tooltip/plugin.ts

@@ -13,6 +13,10 @@ import {
   JupyterLab, JupyterLabPlugin
 } from '../application';
 
+import {
+  BaseCellWidget
+} from '../cells';
+
 import {
   CodeEditor
 } from '../codeeditor';
@@ -25,10 +29,6 @@ import {
   INotebookTracker, NotebookPanel
 } from '../notebook';
 
-import {
-  BaseCellWidget
-} from '../notebook/cells';
-
 import {
   IRenderMime
 } from '../rendermime';

test/src/cells/model.spec.ts

@@ -33,7 +33,7 @@ class TestModel extends CellModel {
 }
 
 
-describe('notebook/cells/model', () => {
+describe('cells/model', () => {
 
   describe('CellModel', () => {
 

test/src/cells/widget.spec.ts

@@ -122,7 +122,7 @@ class LogMarkdownCell extends MarkdownCellWidget {
 }
 
 
-describe('notebook/cells/widget', () => {
+describe('cells/widget', () => {
 
   describe('BaseCellWidget', () => {