diff --git a/internal/archiver/file_saver_test.go b/internal/archiver/file_saver_test.go
index 59a996d76..4dbf78548 100644
--- a/internal/archiver/file_saver_test.go
+++ b/internal/archiver/file_saver_test.go
@@ -30,7 +30,7 @@ func createTestFiles(t testing.TB, num int) (files []string) {
 	return files
 }
 
-func startFileSaver(ctx context.Context, t testing.TB, _ fs.FS) (*fileSaver, context.Context, *errgroup.Group) {
+func startFileSaver(ctx context.Context, t testing.TB, _ fs.FS) (*fileSaver, *mockSaver, context.Context, *errgroup.Group) {
 	wg, ctx := errgroup.WithContext(ctx)
 
 	workers := uint(runtime.NumCPU())
@@ -39,26 +39,26 @@ func startFileSaver(ctx context.Context, t testing.TB, _ fs.FS) (*fileSaver, con
 		t.Fatal(err)
 	}
 
-	s := newFileSaver(ctx, wg, &noopSaver{}, pol, workers)
+	saver := &mockSaver{saved: make(map[string]int)}
+	s := newFileSaver(ctx, wg, saver, pol, workers)
 	s.NodeFromFileInfo = func(snPath, filename string, meta ToNoder, ignoreXattrListError bool) (*data.Node, error) {
 		return meta.ToNode(ignoreXattrListError, t.Logf)
 	}
 
-	return s, ctx, wg
+	return s, saver, ctx, wg
 }
 
 func TestFileSaver(t *testing.T) {
 	ctx, cancel := context.WithCancel(context.Background())
 	defer cancel()
 
-	files := createTestFiles(t, 15)
-
 	startFn := func() {}
 	completeReadingFn := func() {}
 	completeFn := func(*data.Node, ItemStats) {}
 
+	files := createTestFiles(t, 15)
 	testFs := fs.Local{}
-	s, ctx, wg := startFileSaver(ctx, t, testFs)
+	s, saver, ctx, wg := startFileSaver(ctx, t, testFs)
 
 	var results []futureNode
 
@@ -79,6 +79,8 @@ func TestFileSaver(t *testing.T) {
 		}
 	}
 
+	test.Assert(t, len(saver.saved) == len(files), "expected %d saved files, got %d", len(files), len(saver.saved))
+
 	s.TriggerShutdown()
 
 	err := wg.Wait()
diff --git a/internal/archiver/tree_saver_test.go b/internal/archiver/tree_saver_test.go
index 4724f5d5c..ed3a148af 100644
--- a/internal/archiver/tree_saver_test.go
+++ b/internal/archiver/tree_saver_test.go
@@ -4,6 +4,7 @@ import (
 	"context"
 	"fmt"
 	"runtime"
+	"sync"
 	"testing"
 
 	"github.com/restic/restic/internal/data"
@@ -13,10 +14,20 @@ import (
 	"golang.org/x/sync/errgroup"
 )
 
-type noopSaver struct{}
+type mockSaver struct {
+	saved map[string]int
+	mutex sync.Mutex
+}
 
-func (n *noopSaver) SaveBlobAsync(_ context.Context, _ restic.BlobType, buf []byte, id restic.ID, storeDuplicate bool, cb func(newID restic.ID, known bool, sizeInRepo int, err error)) {
-	cb(restic.Hash(buf), false, len(buf), nil)
+func (m *mockSaver) SaveBlobAsync(_ context.Context, _ restic.BlobType, buf []byte, id restic.ID, storeDuplicate bool, cb func(newID restic.ID, known bool, sizeInRepo int, err error)) {
+	// Fake async operation
+	go func() {
+		m.mutex.Lock()
+		m.saved[string(buf)]++
+		m.mutex.Unlock()
+
+		cb(restic.Hash(buf), false, len(buf), nil)
+	}()
 }
 
 func setupTreeSaver() (context.Context, context.CancelFunc, *treeSaver, func() error) {
@@ -27,7 +38,7 @@ func setupTreeSaver() (context.Context, context.CancelFunc, *treeSaver, func() e
 		return err
 	}
 
-	b := newTreeSaver(ctx, wg, uint(runtime.NumCPU()), &noopSaver{}, errFn)
+	b := newTreeSaver(ctx, wg, uint(runtime.NumCPU()), &mockSaver{saved: make(map[string]int)}, errFn)
 
 	shutdown := func() error {
 		b.TriggerShutdown()