diff --git a/shared/nm-utils/nm-test-utils.h b/shared/nm-utils/nm-test-utils.h
index d10ba98dcb..bc4f096820 100644
--- a/shared/nm-utils/nm-test-utils.h
+++ b/shared/nm-utils/nm-test-utils.h
@@ -1056,6 +1056,13 @@ nmtst_g_source_assert_not_called (gpointer user_data)
 	return G_SOURCE_CONTINUE;
 }
 
+static inline gboolean
+nmtst_g_source_nop (gpointer user_data)
+{
+	g_assert (!user_data);
+	return G_SOURCE_CONTINUE;
+}
+
 static inline gboolean
 nmtst_g_source_set_boolean_true (gpointer user_data)
 {