bug#26337: 26.0.50; Command to run tests with latest source

[Tino Calancha <tino.calancha@gmail.com>]

Severity: wishlist

I often while debugging follow this workflow:

1) Make some changes in one branch.
2) Compile Emacs.
3) Run one test file with:
M-& emacs -batch -l ert -l ? -f ert-run-tests-batch-and-exit RET

I never remember the exact command in 3), so i always first check the manual.
We have `ert-run-tests-interactively', but that command won't use
the just compiled sources: you need first to reload the new .elc.

I just wrote one command to do 1-3 above.
Interactively prompts for the file with the tests.
With a prefix argument, also prompts for the selector.  Default to run
all the tests.

Do you think could be worth to have such a command in ert.el?
--8<-----------------------------cut here---------------start------------->8---
commit 14602c92c6e456000b6c2e649b68976f87cd2a4d
Author: Tino Calancha <tino.calancha@gmail.com>
Date:   Sun Apr 2 14:05:51 2017 +0900

    * lisp/emacs-lisp/ert.el (ert-run-tests-batch-in-file): New command.

diff --git a/lisp/emacs-lisp/ert.el b/lisp/emacs-lisp/ert.el
index e7387e463c..c80d8ee5ae 100644
--- a/lisp/emacs-lisp/ert.el
+++ b/lisp/emacs-lisp/ert.el
@@ -1449,6 +1449,41 @@ ert-run-tests-batch
                      (ert-test-name test)))))))
    nil))
 
+(declare-function dired-get-filename "dired" (&optional localp no-error-if-not-filep))
+;;;###autoload
+(defun ert-run-tests-batch-in-file (file &optional selector)
+  "Run the tests in FILE specified by SELECTOR.
+Interactively prompt for FILE.
+Called with a prefix arg prompt for SELECTOR."
+  (interactive
+   (let* ((prefix current-prefix-arg)
+          (def (and (derived-mode-p 'dired-mode) (dired-get-filename)))
+          (file (read-file-name "Run test: " nil def 'mustmatch nil
+                                (lambda (f) (equal "el" (file-name-extension f)))))
+          (test (if (not prefix) "t"
+                  (with-temp-buffer
+                    (insert-file-contents file)
+                    (let (all-tests)
+                      (while (re-search-forward "^\\s-*(ert-deftest \\([^[:blank:]]+\\)" nil t)
+                        (push (match-string-no-properties 1) all-tests))
+                      (unless all-tests
+                        (error "File '%s' doesn't contain any test" file))
+                      (completing-read "Select a test: " all-tests nil 'mustmatch nil nil "t"))))))
+     (list file test)))
+  (if (and (stringp selector) (not (string= selector "t")))
+      (setq selector (concat selector "\\\\'")) "t")
+  (let ((buf (get-buffer-create "*ert*"))
+        (program (expand-file-name invocation-name invocation-directory)))
+    (with-current-buffer buf
+      (let ((inhibit-read-only t))
+        (erase-buffer)
+        (call-process program nil (current-buffer) t
+                      "-batch" "-l" "ert" "-l" file "-eval"
+                      (format
+                       "(ert-run-tests-batch-and-exit\ \"%s\")"
+                       selector))))
+    (display-buffer buf)))
+
 ;;;###autoload
 (defun ert-run-tests-batch-and-exit (&optional selector)
   "Like `ert-run-tests-batch', but exits Emacs when done.
--8<-----------------------------cut here---------------end--------------->8---
In GNU Emacs 26.0.50 (build 1, x86_64-pc-linux-gnu, GTK+ Version 3.22.9)
 of 2017-04-02
Repository revision: a184a7edc58e1e053aa317a0f162df7e225597e1