diff --git a/src/libraries/turtle/function.hpp b/src/libraries/turtle/function.hpp
index a52162e..dcaa43b 100644
--- a/src/libraries/turtle/function.hpp
+++ b/src/libraries/turtle/function.hpp
@@ -92,7 +92,7 @@ namespace mock
 
         void test() const
         {
-            return impl_->test();
+            impl_->test();
         }
 
         result_type operator()() const