diff --git a/test/support/test_iterators.h b/test/support/test_iterators.h
index 5e86f340f..cf164be80 100644
--- a/test/support/test_iterators.h
+++ b/test/support/test_iterators.h
@@ -11,6 +11,7 @@
 #define ITERATORS_H
 
 #include <iterator>
+#include <cassert>
 
 template <class It>
 class output_iterator