bug#29025: Option to run ERT in quiet mode

[Paul Pogonyshev <pogonyshev@gmail.com>]

[-- Attachment #1: Type: text/plain, Size: 532 bytes --]

Severity: wishlist
Tags: patch

When running ERT from command-line with (ert-run-tests-batch ...), it
prints lots of lines for passed tests. The attached patch adds
variable `ert-quiet' that lets you omit such non-important lines:

    (let ((ert-quiet t)) (ert-run-tests-batch ...))

Of course, default is nil, so there is no change for existing
invocations. It is fully backward compatible. Users don't have to
check Emacs version prior to binding this variable: on older version
there will be no effect, but ERT will work.

Paul

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From 689a0faf794908992a0a9a8aebc3a0002ec03508 Mon Sep 17 00:00:00 2001
From: Paul Pogonyshev <pogonyshev@gmail.com>
Date: Fri, 27 Oct 2017 11:35:40 +0200
Subject: [PATCH] Add `ert-quiet' variable.

* ert.el (ert-quiet): New variable.
(ert-run-tests-batch): When `ert-quiet' is non-nil, don't
print non-important information.
---
 lisp/emacs-lisp/ert.el | 33 +++++++++++++++++++--------------
 1 file changed, 19 insertions(+), 14 deletions(-)

diff --git a/lisp/emacs-lisp/ert.el b/lisp/emacs-lisp/ert.el
index 3a3979e81f..1d69af8063 100644
--- a/lisp/emacs-lisp/ert.el
+++ b/lisp/emacs-lisp/ert.el
@@ -1333,6 +1333,9 @@ ert--insert-infos
 
 ;;; Running tests in batch mode.
 
+(defvar ert-quiet nil
+  "Non-nil makes ERT only print important information in batch mode.")
+
 ;;;###autoload
 (defun ert-run-tests-batch (&optional selector)
   "Run the tests specified by SELECTOR, printing results to the terminal.
@@ -1349,10 +1352,11 @@ ert-run-tests-batch
    (lambda (event-type &rest event-args)
      (cl-ecase event-type
        (run-started
-        (cl-destructuring-bind (stats) event-args
-          (message "Running %s tests (%s)"
-                   (length (ert--stats-tests stats))
-                   (ert--format-time-iso8601 (ert--stats-start-time stats)))))
+        (unless ert-quiet
+          (cl-destructuring-bind (stats) event-args
+            (message "Running %s tests (%s)"
+                     (length (ert--stats-tests stats))
+                     (ert--format-time-iso8601 (ert--stats-start-time stats))))))
        (run-ended
         (cl-destructuring-bind (stats abortedp) event-args
           (let ((unexpected (ert-stats-completed-unexpected stats))
@@ -1438,16 +1442,17 @@ ert-run-tests-batch
                         (ert-test-name test)))
               (ert-test-quit
                (message "Quit during %S" (ert-test-name test)))))
-          (let* ((max (prin1-to-string (length (ert--stats-tests stats))))
-                 (format-string (concat "%9s  %"
-                                        (prin1-to-string (length max))
-                                        "s/" max "  %S")))
-            (message format-string
-                     (ert-string-for-test-result result
-                                                 (ert-test-result-expected-p
-                                                  test result))
-                     (1+ (ert--stats-test-pos stats test))
-                     (ert-test-name test)))))))
+          (unless ert-quiet
+            (let* ((max (prin1-to-string (length (ert--stats-tests stats))))
+                   (format-string (concat "%9s  %"
+                                          (prin1-to-string (length max))
+                                          "s/" max "  %S")))
+              (message format-string
+                       (ert-string-for-test-result result
+                                                   (ert-test-result-expected-p
+                                                    test result))
+                       (1+ (ert--stats-test-pos stats test))
+                       (ert-test-name test))))))))
    nil))
 
 ;;;###autoload
-- 
2.14.2