Too strict argument check in `buttercup--enclosed-expr`

[hillu]

In Debian bug 1022352 we can see that the test suite of lua-mode has started failing with buttercup 1.26. It used to run fine with buttercup 1.24.

It seems to me that the expect macro has become stricter about the values it accepts, resulting in error messages such as

Test indent-new-comment-line works when the comment is empty
error: (cl-assertion-failed ((cl-every #'buttercup--wrapper-fun-p (cons arg args)) nil ((lambda nil '(lua-buffer-strs (lua-insert-goto-<> '("-- <>")) (execute-kbd-macro (kbd "M-j"))) (buttercup--mark-stackframe) (butlast (split-string (let ((temp-buffer (generate-new-buffer " *temp*" t))) (save-current-buffer (set-buffer temp-buffer) (unwind-protect (progn (rename-buffer "temp-buffer.lua" t) (let (noninteractive) (lua-mode) (font-lock-mode 1)) (set (make-local-variable 'lua-process) nil) (set (make-local-variable 'lua-process-buffer) nil) (pop-to-buffer (current-buffer)) (unwind-protect (progn (progn (lua-insert-goto-<> '("-- <>")) (execute-kbd-macro (kbd "M-j"))) (buffer-substring-no-properties (point-min) (point-max))) (if (buffer-live-p lua-process-buffer) (progn (lua-kill-process))))) (and (buffer-name temp-buffer) (kill-buffer temp-buffer))))) "\n" nil))) (lambda nil ''("--" "--") (buttercup--mark-stackframe) '("--" "--")))))

I have rewritten those tests to use let expressions, for example by changing …

  (it "works when the comment is empty"
    (expect (lua-buffer-strs
             (lua-insert-goto-<> '("-- <>"))
             (execute-kbd-macro (kbd "M-j")))
            :to-equal
            '("--"
              "--"))
    ;; ...

… to …

  (it "works when the comment is empty"
      (let ((result (lua-buffer-strs
             (lua-insert-goto-<> '("-- <>"))
             (execute-kbd-macro (kbd "M-j")))))
        (expect result
            :to-equal
            '("--"
              "--")))
      ;; ...

Was this change intended? Does my workaround seem sensible or is there maybe a simpler way to fix the breakage?

[snogge]

This is a bug in buttercup, and I have a fix coming.

[snogge]

I have no idea why some uses produce closures and some produce lambda functions. Maybe something with how macros are nested? But, I just noticed that lua-mode/test/test-generic.el does not have lexical-binding set. This is a documented requirement for buttercup. Maybe that's the reason for the discrepancy.

[hillu]

Thank you. I'll try if changing that fixes the errors.

[hillu]

I can report that updating to buttercup 1.28 fixed the problem I reported. Also, adding lexical-binding:t made the otherwise unmodified test suite work with buttercup 1.26. Perhaps it would be a good idea to add a check for lexical-binding to the code run by expect?

Thank you for your help!

[snogge]

Note that the fix in https://github.com/jorgenschaefer/emacs-buttercup/commit/ae884f10ad592ea4b832ea9c7541914d8ecfaf38 means the lua-mode tests pass now.