Add error message if test suite cannot be found (#3585)

* 🚸 add error message if test suite cannot be found

Fixes #3584

tests/src/unit-msgpack.cpp

@@ -15,7 +15,7 @@ using nlohmann::json;
 #include <sstream>
 #include <iomanip>
 #include <set>
-#include <test_data.hpp>
+#include "make_test_data_available.hpp"
 #include "test_utils.hpp"
 
 namespace