assert (guestfs_add_drive (g, NULL) == -1);
assert (guestfs_config (g, NULL, NULL) == -1);
+ /* This optional argument must not be NULL. */
+
+ assert (guestfs_add_drive_opts (g, "/dev/null",
+ GUESTFS_ADD_DRIVE_OPTS_FORMAT, NULL,
+ -1) == -1);
+
/* These can be safely set to NULL, should be no error. */
assert (guestfs_set_path (g, NULL) == 0);