--- a/tests/utils/StringTest.cpp
+++ b/tests/utils/StringTest.cpp
@@ -1,6 +1,7 @@
 //Copyright (c) 2019 Ultimaker B.V.
 //CuraEngine is released under the terms of the AGPLv3 or higher.
 
+#include <iomanip>
 #include <gtest/gtest.h>
 
 #include <../src/utils/IntPoint.h>