Add global instance of null_message_handlert

Author: thomasspriggs

unit/testing-utils/Makefile

@@ -1,6 +1,7 @@
 SRC = \
   c_to_expr.cpp \
   free_form_cmdline.cpp \
+  message.cpp \
   require_expr.cpp \
   require_symbol.cpp \
   run_test_with_compilers.cpp \

unit/testing-utils/message.cpp

@@ -0,0 +1,14 @@
+/*******************************************************************\
+
+ Module: Unit test utilities
+
+ Author: Diffblue Ltd.
+
+\*******************************************************************/
+
+/// \file
+/// Global instance of `null_message_handlert`.
+
+#include "message.h"
+
+null_message_handlert null_message_handler;

unit/testing-utils/message.h

@@ -0,0 +1,16 @@
+/*******************************************************************\
+
+ Module: Unit test utilities
+
+ Author: DiffBlue Limited. All rights reserved.
+
+\*******************************************************************/
+
+#ifndef CPROVER_TESTING_UTILS_MESSAGE_H
+#define CPROVER_TESTING_UTILS_MESSAGE_H
+
+#include <util/message.h>
+
+null_message_handlert extern null_message_handler;
+
+#endif // CPROVER_TESTING_UTILS_MESSAGE_H