diff --git a/lib/cpp/test/EnumTest.cpp b/lib/cpp/test/EnumTest.cpp
index c935bc4..6487906 100644
--- a/lib/cpp/test/EnumTest.cpp
+++ b/lib/cpp/test/EnumTest.cpp
@@ -75,7 +75,7 @@
   BOOST_CHECK_EQUAL(EnumToString(MyEnumWithCustomOstream::CustoM2), "{2:CUSTOM!}");
 
   // some invalid or unknown value
-  MyEnum5::type uut = (MyEnum5::type)44;
+  auto uut = (MyEnum5::type)44;
   BOOST_CHECK_EQUAL(EnumToString(uut), "44");
 }