diff --git a/tests/test.cpp b/tests/test.cpp
index b26e73317f..38c9175f9b 100644
--- a/tests/test.cpp
+++ b/tests/test.cpp
@@ -70,6 +70,14 @@ bool TestApp::OnInit()
 {
     cout << "Test program for wxWidgets\n"
          << "build: " << WX_BUILD_OPTIONS_SIGNATURE << std::endl;
+
+#if !wxUSE_WXVSNPRINTF
+    cout << "\n";
+    cout << "WARNING: VsnprintfTestCase will test the system vsnprintf() function\n";
+    cout << "         instead of the wxWidgets wxVsnprintf_ implementation!" << std::endl;
+    cout << "\n";
+#endif
+
     return wxAppConsole::OnInit();
 };