worker: fix test

worker/upload_test.go

@@ -252,15 +252,17 @@ func TestUploadPackedSlab(t *testing.T) {
 
 	// unblock asynchronous uploads
 	w.UnblockAsyncPackedSlabUploads(params)
-	uploadBytes(1) // ensure bg thread is running
+	uploadBytes(129) // ensure bg thread is running
 
 	// assert packed slabs get uploaded asynchronously
-	err = build.Retry(10, 100*time.Millisecond, func() error {
+	if err = build.Retry(10, 100*time.Millisecond, func() error {
 		if packedSlabsCount() != 0 {
-			return errors.New("expected 0 packed slab")
+			return errors.New("expected 0 packed slabs")
 		}
 		return nil
-	})
+	}); err != nil {
+		t.Fatal(err)
+	}
 }
 
 func TestUploadShards(t *testing.T) {