diff --git a/glib/gtestutils.c b/glib/gtestutils.c
index 046bc017b..c9bc3dd49 100644
--- a/glib/gtestutils.c
+++ b/glib/gtestutils.c
@@ -3431,6 +3431,8 @@ g_test_trap_subprocess (const char           *test_path,
   g_ptr_array_add (argv, NULL);
 
   flags = G_SPAWN_DO_NOT_REAP_CHILD;
+  if (test_log_fd != -1)
+    flags |= G_SPAWN_LEAVE_DESCRIPTORS_OPEN;
   if (test_flags & G_TEST_TRAP_INHERIT_STDIN)
     flags |= G_SPAWN_CHILD_INHERITS_STDIN;