diff --git a/src/infra/install-package-dir.test.ts b/src/infra/install-package-dir.test.ts
index 82bdc89f5bd..05b7328cd91 100644
--- a/src/infra/install-package-dir.test.ts
+++ b/src/infra/install-package-dir.test.ts
@@ -16,14 +16,24 @@ vi.mock("../process/exec.js", async () => {
 
 async function listMatchingDirs(root: string, prefix: string): Promise<string[]> {
   const entries = await fs.readdir(root, { withFileTypes: true });
-  return entries
-    .filter((entry) => entry.isDirectory() && entry.name.startsWith(prefix))
-    .map((entry) => entry.name);
+  const names: string[] = [];
+  for (const entry of entries) {
+    if (entry.isDirectory() && entry.name.startsWith(prefix)) {
+      names.push(entry.name);
+    }
+  }
+  return names;
 }
 
 async function listMatchingEntries(root: string, prefix: string): Promise<string[]> {
   const entries = await fs.readdir(root, { withFileTypes: true });
-  return entries.filter((entry) => entry.name.startsWith(prefix)).map((entry) => entry.name);
+  const names: string[] = [];
+  for (const entry of entries) {
+    if (entry.name.startsWith(prefix)) {
+      names.push(entry.name);
+    }
+  }
+  return names;
 }
 
 function normalizeDarwinTmpPath(filePath: string): string {