diff --git a/core/tests/unit/ldml/test_kmx_plus.cpp b/core/tests/unit/ldml/test_kmx_plus.cpp
index fc3f7e1ffe..5b14043b74 100644
--- a/core/tests/unit/ldml/test_kmx_plus.cpp
+++ b/core/tests/unit/ldml/test_kmx_plus.cpp
@@ -1,3 +1,4 @@
+#include <cstdint>
 #include <test_assert.h>
 #include "kmx/kmx_plus.h"
 #include "kmx/kmx_xstring.h"