fix(core,testing): improve type safety and update tests for latest tstest and storage APIs

test/test.upstream.cache.s3.ts

@@ -89,6 +89,17 @@ tap.test('setup: should create S3 storage backend', async () => {
       }
       return paths;
     },
+    objectExists: async (key: string): Promise<boolean> => {
+      try {
+        const data = await s3Bucket.fastGet({ path: key });
+        return !!data;
+      } catch {
+        return false;
+      }
+    },
+    getMetadata: async (_key: string): Promise<Record<string, string> | null> => {
+      return null;
+    },
   };
 
   expect(storageBackend).toBeTruthy();
@@ -584,9 +595,8 @@ tap.test('cleanup: should stop cache and clean up bucket', async () => {
   // Clean up test bucket
   if (s3Bucket) {
     try {
-      const files = await s3Bucket.fastList({});
-      for (const file of files) {
-        await s3Bucket.fastRemove({ path: file.name });
+      for await (const filePath of s3Bucket.listAllObjects('')) {
+        await s3Bucket.fastRemove({ path: filePath });
       }
       await smartBucket.removeBucket(bucketName);
     } catch {