diff --git a/internal/service/similar_service_test.go b/internal/service/similar_service_test.go
index e8a8a08..d4195ad 100644
--- a/internal/service/similar_service_test.go
+++ b/internal/service/similar_service_test.go
@@ -31,6 +31,20 @@ func (f *fakeEmbeddingRepo) UpsertEmbedding(context.Context, string, uint32, []f
 	return nil
 }
 
+// 向量回填相关方法：近邻服务本身用不到，这里只需满足接口。
+// 回填链路的测试在 handler 层（backstage_embeddings）与本文件的 key 分支单测里覆盖。
+func (f *fakeEmbeddingRepo) ListPendingEmbeddings(context.Context, string, int, int) ([]repository.PendingEmbedding, error) {
+	return nil, nil
+}
+
+func (f *fakeEmbeddingRepo) CountPendingEmbeddings(context.Context, string, int) (int, error) {
+	return 0, nil
+}
+
+func (f *fakeEmbeddingRepo) RecordEmbeddingFailure(context.Context, string, uint32, string) error {
+	return nil
+}
+
 func (f *fakeEmbeddingRepo) BulkUpsertEmbedding(context.Context, string, []uint32, [][]float32) error {
 	return nil
 }