diff --git a/src/testdir/test_retab.vim b/src/testdir/test_retab.vim
index b792da5..c7190aa 100644
--- a/src/testdir/test_retab.vim
+++ b/src/testdir/test_retab.vim
@@ -75,6 +75,9 @@
 func Test_retab_error()
   call assert_fails('retab -1',  'E487:')
   call assert_fails('retab! -1', 'E487:')
+  call assert_fails('ret -1000', 'E487:')
+  call assert_fails('ret 10000', 'E475:')
+  call assert_fails('ret 80000000000000000000', 'E475:')
 endfunc
 
 " vim: shiftwidth=2 sts=2 expandtab