diff --git a/untests/doctest/doctest.hpp b/untests/doctest/doctest.hpp
index 2c0032e..139d4b6 100644
--- a/untests/doctest/doctest.hpp
+++ b/untests/doctest/doctest.hpp
@@ -2,6 +2,9 @@
 
 #include "doctest.h"
 
+// https://github.com/onqtam/doctest/issues/126
+#include <iostream>
+
 #define STATIC_CHECK(...)\
     static_assert(__VA_ARGS__, #__VA_ARGS__);\
     CHECK(__VA_ARGS__)