Apply suggestions from code review

Co-authored-by: Elizabeth Craig <ecraig12345@gmail.com>

Author: ecraig12345

packages/test-utilities/package.json

@@ -1,7 +1,7 @@
 {
   "name": "@lage-run/test-utilities",
   "version": "0.1.0",
-  "description": "Test utilities",
+  "description": "Internal test utilities for lage",
   "private": true,
   "repository": {
     "url": "https://github.com/microsoft/lage"

packages/test-utilities/src/removeTempDir.ts

@@ -9,10 +9,11 @@ import * as fs from "fs";
  * removal methods directly.
  *
  * @returns Whether deleting the directory succeeded.
+ * If `dir` was undefined or empty, it's a no-op and returns true.
  */
-export function removeTempDir(dir: string): boolean {
+export function removeTempDir(dir: string | undefined): boolean {
   try {
-    fs.rmSync(dir, { recursive: true, force: true });
+    dir && fs.rmSync(dir, { recursive: true, force: true });
     return true;
   } catch {
     return false;