diff --git a/tests/example1_macro.mod b/tests/example1_macro.mod
index 0db3221ec..06a0fd918 100644
--- a/tests/example1_macro.mod
+++ b/tests/example1_macro.mod
@@ -157,3 +157,7 @@ stoch_simul;
 @#error "String comparison"
 @#endif
 
+@#define f(x) = x + "C"
+@#if "A" + f("B") != "ABC"
+@#error "Problem with String concatenation"
+@#endif