diff --git a/common/engine/keyboardprocessor/tests/unit/kmx/kmx.cpp b/common/engine/keyboardprocessor/tests/unit/kmx/kmx.cpp
index b3df7ab820..821dcf09f6 100644
--- a/common/engine/keyboardprocessor/tests/unit/kmx/kmx.cpp
+++ b/common/engine/keyboardprocessor/tests/unit/kmx/kmx.cpp
@@ -8,6 +8,7 @@
 #include <fstream>
 #include <sstream>
 #include <cctype>
+#include <algorithm>
 #include <keyman/keyboardprocessor.h>
 #include "state.hpp"