From d61d7dd95e27b8a1291b026a5ff9e02ac0d87e99 Mon Sep 17 00:00:00 2001
From: Johannes Rieken <johannes.rieken@gmail.com>
Date: Fri, 29 May 2020 16:59:36 +0200
Subject: [PATCH] fix notebook tests

---
 src/vs/workbench/api/common/extHostNotebook.ts | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/vs/workbench/api/common/extHostNotebook.ts b/src/vs/workbench/api/common/extHostNotebook.ts
index 61b31818789..ffd18d967f8 100644
--- a/src/vs/workbench/api/common/extHostNotebook.ts
+++ b/src/vs/workbench/api/common/extHostNotebook.ts
@@ -816,9 +816,9 @@ export class ExtHostNotebookController implements ExtHostNotebookShape, ExtHostN
 
 		this._notebookContentProviders.set(viewType, { extension, provider });
 
-		const listener = provider.onDidChangeNotebook(e => {
-			this._proxy.$onNotebookChange(viewType, e.document.uri);
-		});
+		const listener = provider.onDidChangeNotebook
+			? provider.onDidChangeNotebook(e => this._proxy.$onNotebookChange(viewType, e.document.uri))
+			: Disposable.None;
 
 		this._proxy.$registerNotebookProvider({ id: extension.identifier, location: extension.extensionLocation }, viewType, provider.kernel ? { id: viewType, label: provider.kernel.label, extensionLocation: extension.extensionLocation, preloads: provider.kernel.preloads } : undefined);
 		return new extHostTypes.Disposable(() => {