diff --git a/src/vs/workbench/api/browser/mainThreadNotebook.ts b/src/vs/workbench/api/browser/mainThreadNotebook.ts
index 00b9d20b32fdb17feedf513ea50451ef14365f48..ae0e9662b6475685e0c229cdf7da2667753288aa 100644
--- a/src/vs/workbench/api/browser/mainThreadNotebook.ts
+++ b/src/vs/workbench/api/browser/mainThreadNotebook.ts
@@ -18,7 +18,7 @@ import { INotebookEditor } from 'vs/workbench/contrib/notebook/browser/notebookB
 import { NotebookCellTextModel } from 'vs/workbench/contrib/notebook/common/model/notebookCellTextModel';
 import { NotebookTextModel } from 'vs/workbench/contrib/notebook/common/model/notebookTextModel';
 import { INotebookCellStatusBarService } from 'vs/workbench/contrib/notebook/common/notebookCellStatusBarService';
-import { ACCESSIBLE_NOTEBOOK_DISPLAY_ORDER, CellEditType, CellKind, DisplayOrderKey, ICellEditOperation, ICellRange, IEditor, IMainCellDto, INotebookDocumentFilter, NotebookCellMetadata, NotebookCellOutputsSplice, NotebookCellsChangeType, NotebookDocumentMetadata, NOTEBOOK_DISPLAY_ORDER, TransientMetadata } from 'vs/workbench/contrib/notebook/common/notebookCommon';
+import { ACCESSIBLE_NOTEBOOK_DISPLAY_ORDER, CellEditType, DisplayOrderKey, ICellEditOperation, ICellRange, IEditor, IMainCellDto, INotebookDocumentFilter, NotebookCellMetadata, NotebookCellOutputsSplice, NotebookCellsChangeType, NotebookDocumentMetadata, NOTEBOOK_DISPLAY_ORDER, TransientMetadata } from 'vs/workbench/contrib/notebook/common/notebookCommon';
 import { IMainNotebookController, INotebookService } from 'vs/workbench/contrib/notebook/common/notebookService';
 import { IEditorService } from 'vs/workbench/services/editor/common/editorService';
 import { IWorkingCopyService } from 'vs/workbench/services/workingCopy/common/workingCopyService';
diff --git a/src/vs/workbench/contrib/notebook/common/model/notebookTextModel.ts b/src/vs/workbench/contrib/notebook/common/model/notebookTextModel.ts
index 6d9d8078e6e8875541cb59e34dab6024f9580bc2..a265a6d36aaf5ef1e849e4bcac785dd7148dc631 100644
--- a/src/vs/workbench/contrib/notebook/common/model/notebookTextModel.ts
+++ b/src/vs/workbench/contrib/notebook/common/model/notebookTextModel.ts
@@ -131,7 +131,7 @@ export class NotebookTextModel extends Disposable implements INotebookTextModel
 	private _cellhandlePool: number = 0;
 	private _mapping: Map<number, NotebookCellTextModel> = new Map();
 	private _cellListeners: Map<number, IDisposable> = new Map();
-	private _cells: NotebookCellTextModel[];
+	private _cells: NotebookCellTextModel[] = [];
 	private _languages: string[] = [];
 	private _allLanguages: boolean = false;
 
diff --git a/src/vs/workbench/contrib/notebook/test/notebookViewModel.test.ts b/src/vs/workbench/contrib/notebook/test/notebookViewModel.test.ts
index 92eae8a9b4a6156576781cdbffe8344f8e520030..a8d48a6870b7ff78ada928d30a96f25a7ccd854f 100644
--- a/src/vs/workbench/contrib/notebook/test/notebookViewModel.test.ts
+++ b/src/vs/workbench/contrib/notebook/test/notebookViewModel.test.ts
@@ -6,7 +6,7 @@
 import * as assert from 'assert';
 import { URI } from 'vs/base/common/uri';
 import { NotebookViewModel } from 'vs/workbench/contrib/notebook/browser/viewModel/notebookViewModel';
-import { CellKind, NotebookCellMetadata, diff, ICellRange } from 'vs/workbench/contrib/notebook/common/notebookCommon';
+import { CellKind, NotebookCellMetadata, diff, ICellRange, notebookDocumentMetadataDefaults } from 'vs/workbench/contrib/notebook/common/notebookCommon';
 import { withTestNotebook, TestCell, NotebookEditorTestModel, setupInstantiationService } from 'vs/workbench/contrib/notebook/test/testNotebookEditor';
 import { IBulkEditService } from 'vs/editor/browser/services/bulkEditService';
 import { IUndoRedoService } from 'vs/platform/undoRedo/common/undoRedo';
@@ -25,7 +25,7 @@ suite('NotebookViewModel', () => {
 	const modeService = instantiationService.get(IModeService);
 
 	test('ctor', function () {
-		const notebook = new NotebookTextModel('notebook', false, URI.parse('test'), undoRedoService, textModelService, modeService);
+		const notebook = new NotebookTextModel('notebook', false, URI.parse('test'), [], [], notebookDocumentMetadataDefaults, { transientMetadata: {}, transientOutputs: false }, undoRedoService, textModelService, modeService);
 		const model = new NotebookEditorTestModel(notebook);
 		const eventDispatcher = new NotebookEventDispatcher();
 		const viewModel = new NotebookViewModel('notebook', model.notebook, eventDispatcher, null, instantiationService, blukEditService, undoRedoService);