diff --git a/extensions/vscode-api-tests/src/singlefolder-tests/notebook.document.test.ts b/extensions/vscode-api-tests/src/singlefolder-tests/notebook.document.test.ts
index 0d5ecc671fa..e0a8912e0f6 100644
--- a/extensions/vscode-api-tests/src/singlefolder-tests/notebook.document.test.ts
+++ b/extensions/vscode-api-tests/src/singlefolder-tests/notebook.document.test.ts
@@ -232,4 +232,65 @@ suite('Notebook Document', function () {
 		assert.strictEqual(data.changes[0].items[0], document.cells[0]);
 		assert.strictEqual(data.changes[0].items[1], document.cells[1]);
 	});
+
+	test('workspace edit API (appendNotebookCellOutput, replaceCellOutput, event)', async function () {
+		const uri = await utils.createRandomFile(undefined, undefined, '.nbdtest');
+		const document = await vscode.notebook.openNotebookDocument(uri);
+
+		const outputChangeEvent = utils.asPromise<vscode.NotebookCellOutputsChangeEvent>(vscode.notebook.onDidChangeCellOutputs);
+		const edit = new vscode.WorkspaceEdit();
+		const firstCellOutput = new vscode.NotebookCellOutput([new vscode.NotebookCellOutputItem('foo', 'bar')]);
+		edit.appendNotebookCellOutput(document.uri, 0, [firstCellOutput]);
+		const success = await vscode.workspace.applyEdit(edit);
+		const data = await outputChangeEvent;
+
+		assert.strictEqual(success, true);
+		assert.strictEqual(document.cells.length, 1);
+		assert.strictEqual(document.cells[0].outputs.length, 1);
+		assert.deepStrictEqual(document.cells[0].outputs, [firstCellOutput]);
+
+		assert.strictEqual(data.document === document, true);
+		assert.strictEqual(data.cells.length, 1);
+		assert.strictEqual(data.cells[0].outputs.length, 1);
+		assert.deepStrictEqual(data.cells[0].outputs, [firstCellOutput]);
+
+
+		{
+			const outputChangeEvent = utils.asPromise<vscode.NotebookCellOutputsChangeEvent>(vscode.notebook.onDidChangeCellOutputs);
+			const edit = new vscode.WorkspaceEdit();
+			const secondCellOutput = new vscode.NotebookCellOutput([new vscode.NotebookCellOutputItem('foo', 'baz')]);
+			edit.appendNotebookCellOutput(document.uri, 0, [secondCellOutput]);
+			const success = await vscode.workspace.applyEdit(edit);
+			const data = await outputChangeEvent;
+
+			assert.strictEqual(success, true);
+			assert.strictEqual(document.cells.length, 1);
+			assert.strictEqual(document.cells[0].outputs.length, 2);
+			assert.deepStrictEqual(document.cells[0].outputs, [firstCellOutput, secondCellOutput]);
+
+			assert.strictEqual(data.document === document, true);
+			assert.strictEqual(data.cells.length, 1);
+			assert.strictEqual(data.cells[0].outputs.length, 2);
+			assert.deepStrictEqual(data.cells[0].outputs, [firstCellOutput, secondCellOutput]);
+		}
+
+		{
+			const outputChangeEvent = utils.asPromise<vscode.NotebookCellOutputsChangeEvent>(vscode.notebook.onDidChangeCellOutputs);
+			const edit = new vscode.WorkspaceEdit();
+			const thirdOutput = new vscode.NotebookCellOutput([new vscode.NotebookCellOutputItem('foo', 'baz1')]);
+			edit.replaceNotebookCellOutput(document.uri, 0, [thirdOutput]);
+			const success = await vscode.workspace.applyEdit(edit);
+			const data = await outputChangeEvent;
+
+			assert.strictEqual(success, true);
+			assert.strictEqual(document.cells.length, 1);
+			assert.strictEqual(document.cells[0].outputs.length, 1);
+			assert.deepStrictEqual(document.cells[0].outputs, [thirdOutput]);
+
+			assert.strictEqual(data.document === document, true);
+			assert.strictEqual(data.cells.length, 1);
+			assert.strictEqual(data.cells[0].outputs.length, 1);
+			assert.deepStrictEqual(data.cells[0].outputs, [thirdOutput]);
+		}
+	});
 });
diff --git a/extensions/vscode-api-tests/src/singlefolder-tests/notebook.test.ts b/extensions/vscode-api-tests/src/singlefolder-tests/notebook.test.ts
index e27ca9afcaa..c246577b062 100644
--- a/extensions/vscode-api-tests/src/singlefolder-tests/notebook.test.ts
+++ b/extensions/vscode-api-tests/src/singlefolder-tests/notebook.test.ts
@@ -429,99 +429,6 @@ suite('Notebook API tests', function () {
 		await saveAllFilesAndCloseAll(resource);
 	});
 
-	test('edit API (replaceCells)', async function () {
-		const resource = await createRandomFile('', undefined, '.vsctestnb');
-		await vscode.commands.executeCommand('vscode.openWith', resource, 'notebookCoreTest');
-
-		const cellsChangeEvent = asPromise<vscode.NotebookCellsChangeEvent>(vscode.notebook.onDidChangeNotebookCells);
-		await vscode.window.activeNotebookEditor!.edit(editBuilder => {
-			editBuilder.replaceCells(1, 0, [{ cellKind: vscode.NotebookCellKind.Code, language: 'javascript', source: 'test 2', outputs: [], metadata: undefined }]);
-		});
-
-		const cellChangeEventRet = await cellsChangeEvent;
-		assert.strictEqual(cellChangeEventRet.document === vscode.window.activeNotebookEditor?.document, true);
-		assert.strictEqual(cellChangeEventRet.document.isDirty, true);
-		assert.strictEqual(cellChangeEventRet.changes.length, 1);
-		assert.strictEqual(cellChangeEventRet.changes[0].start, 1);
-		assert.strictEqual(cellChangeEventRet.changes[0].deletedCount, 0);
-		assert.strictEqual(cellChangeEventRet.changes[0].items[0] === vscode.window.activeNotebookEditor!.document.cells[1], true);
-
-		await saveAllFilesAndCloseAll(resource);
-	});
-
-	test('edit API (replaceOutput, USE NotebookCellOutput-type)', async function () {
-		const resource = await createRandomFile('', undefined, '.vsctestnb');
-		await vscode.commands.executeCommand('vscode.openWith', resource, 'notebookCoreTest');
-
-		await vscode.window.activeNotebookEditor!.edit(editBuilder => {
-			editBuilder.replaceCellOutput(0, [new vscode.NotebookCellOutput([
-				new vscode.NotebookCellOutputItem('application/foo', 'bar'),
-				new vscode.NotebookCellOutputItem('application/json', { data: true }, { metadata: true }),
-			])]);
-		});
-
-		const document = vscode.window.activeNotebookEditor?.document!;
-		assert.strictEqual(document.isDirty, true);
-		assert.strictEqual(document.cells.length, 1);
-		assert.strictEqual(document.cells[0].outputs.length, 1);
-
-		// consuming is OLD api (for now)
-		const [output] = document.cells[0].outputs;
-
-		assert.strictEqual(output.outputs.length, 2);
-		assert.strictEqual(output.outputs[0].mime, 'application/foo');
-		assert.strictEqual(output.outputs[0].value, 'bar');
-		assert.strictEqual(output.outputs[1].mime, 'application/json');
-		assert.deepStrictEqual(output.outputs[1].value, { data: true });
-
-		await saveAllFilesAndCloseAll(undefined);
-	});
-
-	test('edit API (replaceOutput)', async function () {
-		const resource = await createRandomFile('', undefined, '.vsctestnb');
-		await vscode.commands.executeCommand('vscode.openWith', resource, 'notebookCoreTest');
-
-		await vscode.window.activeNotebookEditor!.edit(editBuilder => {
-			editBuilder.replaceCellOutput(0, [new vscode.NotebookCellOutput([
-				new vscode.NotebookCellOutputItem('foo', 'bar')
-			])]);
-		});
-
-		const document = vscode.window.activeNotebookEditor?.document!;
-		assert.strictEqual(document.isDirty, true);
-		assert.strictEqual(document.cells.length, 1);
-		assert.strictEqual(document.cells[0].outputs.length, 1);
-		assert.strictEqual(document.cells[0].outputs[0].outputs.length, 1);
-		assert.strictEqual(document.cells[0].outputs[0].outputs[0].mime, 'foo');
-		assert.strictEqual(document.cells[0].outputs[0].outputs[0].value, 'bar');
-
-		await saveAllFilesAndCloseAll(undefined);
-	});
-
-	test('edit API (replaceOutput, event)', async function () {
-		const resource = await createRandomFile('', undefined, '.vsctestnb');
-		await vscode.commands.executeCommand('vscode.openWith', resource, 'notebookCoreTest');
-
-		const outputChangeEvent = asPromise<vscode.NotebookCellOutputsChangeEvent>(vscode.notebook.onDidChangeCellOutputs);
-		await vscode.window.activeNotebookEditor!.edit(editBuilder => {
-			editBuilder.replaceCellOutput(0, [new vscode.NotebookCellOutput([
-				new vscode.NotebookCellOutputItem('foo', 'bar')
-			])]);
-		});
-
-		const value = await outputChangeEvent;
-		assert.strictEqual(value.document === vscode.window.activeNotebookEditor?.document, true);
-		assert.strictEqual(value.document.isDirty, true);
-		assert.strictEqual(value.cells.length, 1);
-		assert.strictEqual(value.document.cells.length, 1);
-		assert.strictEqual(value.document.cells[0].outputs.length, 1);
-		assert.strictEqual(value.document.cells[0].outputs[0].outputs.length, 1);
-		assert.strictEqual(value.document.cells[0].outputs[0].outputs[0].mime, 'foo');
-		assert.strictEqual(value.document.cells[0].outputs[0].outputs[0].value, 'bar');
-
-		await saveAllFilesAndCloseAll(undefined);
-	});
-
 	test('edit API (replaceMetadata)', async function () {
 		const resource = await createRandomFile('', undefined, '.vsctestnb');
 		await vscode.commands.executeCommand('vscode.openWith', resource, 'notebookCoreTest');