diff --git a/tests/testutil_monitoring.cpp b/tests/testutil_monitoring.cpp
index 3afb455f..75bd763c 100644
--- a/tests/testutil_monitoring.cpp
+++ b/tests/testutil_monitoring.cpp
@@ -112,12 +112,12 @@ void expect_monitor_event (void *monitor_, int expected_event_)
                            get_monitor_event (monitor_, NULL, NULL));
 }
 
-void print_unexpected_event (char *buf_,
-                             size_t buf_size_,
-                             int event_,
-                             int err_,
-                             int expected_event_,
-                             int expected_err_)
+static void print_unexpected_event (char *buf_,
+                                    size_t buf_size_,
+                                    int event_,
+                                    int err_,
+                                    int expected_event_,
+                                    int expected_err_)
 {
     snprintf (buf_, buf_size_,
               "Unexpected event: 0x%x, value = %i/0x%x (expected: 0x%x, value "
diff --git a/tests/testutil_monitoring.hpp b/tests/testutil_monitoring.hpp
index e6b1e328..d9490104 100644
--- a/tests/testutil_monitoring.hpp
+++ b/tests/testutil_monitoring.hpp
@@ -46,13 +46,6 @@ int get_monitor_event (void *monitor_, int *value_, char **address_);
 
 void expect_monitor_event (void *monitor_, int expected_event_);
 
-void print_unexpected_event (char *buf_,
-                             size_t buf_size_,
-                             int event_,
-                             int err_,
-                             int expected_event_,
-                             int expected_err_);
-
 void print_unexpected_event_stderr (int event_,
                                     int err_,
                                     int expected_event_,
diff --git a/tests/testutil_security.cpp b/tests/testutil_security.cpp
index 90803e4d..8dca6471 100644
--- a/tests/testutil_security.cpp
+++ b/tests/testutil_security.cpp
@@ -263,9 +263,9 @@ void zap_handler (void *)
     zap_handler_generic (zap_ok);
 }
 
-void setup_handshake_socket_monitor (void *server_,
-                                     void **server_mon_,
-                                     const char *monitor_endpoint_)
+static void setup_handshake_socket_monitor (void *server_,
+                                            void **server_mon_,
+                                            const char *monitor_endpoint_)
 {
     //  Monitor handshake events on the server
     TEST_ASSERT_SUCCESS_ERRNO (zmq_socket_monitor (
diff --git a/tests/testutil_security.hpp b/tests/testutil_security.hpp
index cb4ee4e2..909bbeb9 100644
--- a/tests/testutil_security.hpp
+++ b/tests/testutil_security.hpp
@@ -122,10 +122,6 @@ void zap_handler (void * /*unused_*/);
         TEST_ASSERT_EQUAL_INT (0, event_count);                                       \
     }
 
-void setup_handshake_socket_monitor (void *server_,
-                                     void **server_mon_,
-                                     const char *monitor_endpoint_);
-
 void setup_context_and_server_side (
   void **zap_control_,
   void **zap_thread_,