test(cleanup): fix temporary directory leaks in test suites (#26217)

packages/test-utils/src/file-system-test-helpers.ts

@@ -93,6 +93,25 @@ export async function createTmpDir(
  * Cleans up (deletes) a temporary directory and its contents.
  * @param dir The absolute path to the temporary directory to clean up.
  */
-export async function cleanupTmpDir(dir: string) {
-  await fs.rm(dir, { recursive: true, force: true });
+export async function cleanupTmpDir(dir: string | undefined) {
+  if (!dir) {
+    return;
+  }
+
+  try {
+    const exists = await fs
+      .access(dir)
+      .then(() => true)
+      .catch(() => false);
+
+    if (exists) {
+      if (process.platform === 'win32') {
+        // Give Windows a moment to release file handles
+        await new Promise((resolve) => setTimeout(resolve, 100));
+      }
+      await fs.rm(dir, { recursive: true, force: true });
+    }
+  } catch {
+    // Ignore errors during cleanup (e.g., directory already deleted)
+  }
 }