diff --git a/unit/analyses/ai/ai.cpp b/unit/analyses/ai/ai.cpp
index f37c0c4f400..5aee8d8fd83 100644
--- a/unit/analyses/ai/ai.cpp
+++ b/unit/analyses/ai/ai.cpp
@@ -10,6 +10,7 @@
 /// Unit tests for ait
 
 #include <testing-utils/catch.hpp>
+#include <testing-utils/message.h>
 
 #include <analyses/ai.h>
 
@@ -239,8 +240,7 @@ SCENARIO(
 
   goto_model.symbol_table.add(start);
 
-  null_message_handlert nullout;
-  goto_convert(goto_model, nullout);
+  goto_convert(goto_model, null_message_handler);
 
   WHEN("The target program is analysed")
   {
diff --git a/unit/analyses/constant_propagator.cpp b/unit/analyses/constant_propagator.cpp
index 8c591e1a63c..0c2936b5982 100644
--- a/unit/analyses/constant_propagator.cpp
+++ b/unit/analyses/constant_propagator.cpp
@@ -7,6 +7,7 @@ Author: Diffblue Ltd
 \*******************************************************************/
 
 #include <testing-utils/catch.hpp>
+#include <testing-utils/message.h>
 
 #include <analyses/constant_propagator.h>
 
@@ -14,8 +15,6 @@ Author: Diffblue Ltd
 
 #include <goto-programs/goto_convert_functions.h>
 
-#include <util/message.h>
-
 static bool starts_with_x(const exprt &e, const namespacet &)
 {
   if(e.id() != ID_symbol)
@@ -27,8 +26,6 @@ SCENARIO("constant_propagator", "[core][analyses][constant_propagator]")
 {
   GIVEN("A simple GOTO program")
   {
-    null_message_handlert null_out;
-
     goto_modelt goto_model;
     namespacet ns(goto_model.symbol_table);
 
@@ -65,7 +62,7 @@ SCENARIO("constant_propagator", "[core][analyses][constant_propagator]")
     goto_model.symbol_table.add(local_y);
     goto_model.symbol_table.add(main_function_symbol);
 
-    goto_convert(goto_model, null_out);
+    goto_convert(goto_model, null_message_handler);
 
     const goto_functiont &main_function = goto_model.get_goto_function("main");
 
diff --git a/unit/path_strategies.cpp b/unit/path_strategies.cpp
index 92b6c292599..1ad321d6887 100644
--- a/unit/path_strategies.cpp
+++ b/unit/path_strategies.cpp
@@ -25,7 +25,6 @@ Author: Kareem Khazem <karkhaz@karkhaz.com>, 2018
 
 #include <util/cmdline.h>
 #include <util/config.h>
-#include <util/cout_message.h>
 #include <util/tempfile.h>
 
 // The actual test suite.