diff --git a/extensions/vscode-api-tests/src/singlefolder-tests/commands.test.ts b/extensions/vscode-api-tests/src/singlefolder-tests/commands.test.ts
index d7cbc2afc4e..315e94e9be4 100644
--- a/extensions/vscode-api-tests/src/singlefolder-tests/commands.test.ts
+++ b/extensions/vscode-api-tests/src/singlefolder-tests/commands.test.ts
@@ -111,17 +111,22 @@ suite('vscode API - commands', () => {
 	});
 
 	test('api-command: vscode.open', async function () {
-		const uri = Uri.parse(workspace.workspaceFolders![0].uri.toString() + '/far.js');
+		assert.ok(workspace.workspaceFolders);
+		assert.ok(workspace.workspaceFolders.length > 0);
+		const uri = Uri.parse(workspace.workspaceFolders[0].uri.toString() + '/far.js');
 
 		await commands.executeCommand('vscode.open', uri);
+		assert.strictEqual(window.tabGroups.all.length, 1);
 		assert.strictEqual(window.tabGroups.all[0].activeTab?.group.viewColumn, ViewColumn.One);
 		assert.strictEqual(window.activeTextEditor?.viewColumn, ViewColumn.One);
 
 		await commands.executeCommand('vscode.open', uri, ViewColumn.Two);
+		assert.strictEqual(window.tabGroups.all.length, 2);
 		assert.strictEqual(window.tabGroups.all[1].activeTab?.group.viewColumn, ViewColumn.Two);
 		assert.strictEqual(window.activeTextEditor?.viewColumn, ViewColumn.Two);
 
 		await commands.executeCommand('vscode.open', uri, ViewColumn.One);
+		assert.strictEqual(window.tabGroups.all.length, 2);
 		assert.strictEqual(window.tabGroups.all[0].activeTab?.group.viewColumn, ViewColumn.One);
 		assert.strictEqual(window.activeTextEditor?.viewColumn, ViewColumn.One);