diff --git a/emacs/test-flan.el b/emacs/test-flan.el
index 7712e455..ac784a90 100644
--- a/emacs/test-flan.el
+++ b/emacs/test-flan.el
@@ -47,6 +47,11 @@ already rely on it — so nothing here is a stand-in for the real thing."
     (setq test-flan--failures (1+ test-flan--failures))
     (message "  FAIL %s" name)))
 
+;; Taken from `command-line-args', and the leftovers cleared: whatever is
+;; still in `command-line-args-left' when this file finishes, Emacs visits as
+;; a file, and visiting the compiler binary asks a yes-or-no question about
+;; its size that a batch Emacs waits on forever.
+(setq command-line-args-left nil)
 (let* ((args (cdr (member "--" command-line-args)))
        (socket (nth 0 args))
        (file   (nth 1 args))