diff --git a/glib/gtestutils.h b/glib/gtestutils.h
index 688f2eae7..30ede2588 100644
--- a/glib/gtestutils.h
+++ b/glib/gtestutils.h
@@ -54,7 +54,7 @@ typedef void (*GTestFixtureFunc) (gpointer      fixture,
                                              gint64 __n1 = (n1), __n2 = (n2); \
                                              if (__n1 cmp __n2) ; else \
                                                g_assertion_message_cmpint (G_LOG_DOMAIN, __FILE__, __LINE__, G_STRFUNC, \
-                                                 #n1 " " #cmp " " #n2, __n1, #cmp, __n2, 'i'); \
+                                                 #n1 " " #cmp " " #n2, (guint64)__n1, #cmp, (guint64)__n2, 'i'); \
                                         } G_STMT_END
 #define g_assert_cmpuint(n1, cmp, n2)   G_STMT_START { \
                                              guint64 __n1 = (n1), __n2 = (n2); \
diff --git a/glib/tests/meson.build b/glib/tests/meson.build
index e84e986d8..f8c57a972 100644
--- a/glib/tests/meson.build
+++ b/glib/tests/meson.build
@@ -138,6 +138,13 @@ glib_tests = {
     'args': [ '--verbose' ],
     'extra_programs' : ['testing-helper'],
   },
+  'testing-macro' : {
+    'args': [ '--verbose' ],
+    'extra_programs' : ['testing-helper'],
+    'source' : 'testing.c',
+    'c_args' : cc.get_id() == 'gcc' ? ['-Werror=sign-conversion'] : [],
+    'install' : false,
+  },
   'test-printf' : {},
   'thread' : {},
   'thread-deprecated' : {},
diff --git a/glib/tests/testing.c b/glib/tests/testing.c
index e7baf7ca2..acbc1be22 100644
--- a/glib/tests/testing.c
+++ b/glib/tests/testing.c
@@ -486,7 +486,7 @@ test_random_conversions (void)
   int vint = g_test_rand_int();
   char *err, *str = g_strdup_printf ("%d", vint);
   gint64 vint64 = g_ascii_strtoll (str, &err, 10);
-  g_assert_cmphex (vint, ==, vint64);
+  g_assert_cmpint (vint, ==, vint64);
   g_assert_true (!err || *err == 0);
   g_free (str);
 }