diff --git a/test/hei_user_defines.cpp b/test/hei_user_defines.cpp
new file mode 100644
index 0000000..f6e39f0
--- /dev/null
+++ b/test/hei_user_defines.cpp
@@ -0,0 +1,30 @@
+#include <assert.h>
+#include <stdarg.h>
+#include <stdio.h>
+
+namespace libhei
+{
+
+void hei_inf(char* format, ...)
+{
+    va_list args;
+
+    printf("I> ");
+    va_start(args, format);
+    vprintf(format, args);
+    va_end(args);
+    printf("\n");
+}
+
+void hei_err(char* format, ...)
+{
+    va_list args;
+
+    printf("E> ");
+    va_start(args, format);
+    vprintf(format, args);
+    va_end(args);
+    printf("\n");
+}
+
+} // namespace libhei