diff --git a/src/testdir/test_vim9_script.vim b/src/testdir/test_vim9_script.vim
index 0d9586d..94be7c1 100644
--- a/src/testdir/test_vim9_script.vim
+++ b/src/testdir/test_vim9_script.vim
@@ -3278,7 +3278,8 @@
       while job_status(myjob) == 'run'
         sleep 10m
       endwhile
-      sleep 10m
+      # wait for Exit_cb() to be called
+      sleep 100m
   END
   writefile(lines, 'Xdef')
   assert_fails('so Xdef', ['E684:', 'E1012:'])