diff --git a/test_http_server.cc b/test_http_server.cc
index 2955e79..39a12ed 100644
--- a/test_http_server.cc
+++ b/test_http_server.cc
@@ -494,7 +494,7 @@
     CHECK_EQ(terms.size(), num_terms);
   }
 
-  inline string Get(const off_t index) const {
+  inline const string& Get(const off_t index) const {
     return terms[index];
   }
   inline const char *GetCStr(const off_t index) const {