diff --git a/tests/test_optional.cpp b/tests/test_optional.cpp
index 6240f53f3c4edf209aba54235ca29d9195fe50bd..35b74a470cea3e82a230592454126d04ce092da9 100644
--- a/tests/test_optional.cpp
+++ b/tests/test_optional.cpp
@@ -90,8 +90,8 @@ TEST(optionalm,assign_returns) {
 
 TEST(optionalm,assign_reference) {
     double a=3.0;
-    optional<double &> ar;
-    optional<double &> br;
+    optional<double&> ar;
+    optional<double&> br;
 
     ar = a;
     EXPECT_TRUE(ar);