Subject: Re: bug#47320: Improve failure reporting in test/lisp/electrict-tests.el

From: Alan Mackenzie <[email-masked]>
Date: Wed, 24 Mar 2021 13:46:57 +0000

Hello, João,

Thanks for the positive reaction!

On Tue, Mar 23, 2021 at 15:59:03 +0000, João Távora wrote:
> As the author of electric-tests.el, I'm fine with either approach.
> Michael's would seem more integrated, at a glance, not sure how hard it is
> to switch to it. I'd have to see that patch. João

I'm having some difficulty getting my head around the "explanation"
functionality of ert, which leans me towards my initial plan.

Here's the patch (actually written quite a long time ago) I would like to
merge into electric-tests.el:

diff --git a/test/lisp/electric-tests.el b/test/lisp/electric-tests.el
index 62a42b7fe4..44b3d8b672 100644
--- a/test/lisp/electric-tests.el
+++ b/test/lisp/electric-tests.el
@@ -50,7 +50,8 @@ save-electric-modes
   `(call-with-saved-electric-modes #'(lambda () ,@body)))
 
 (defun electric-pair-test-for (fixture where char expected-string
-                                       expected-point mode bindings fixture-fn)
+                                       expected-point mode bindings
+                                       fixture-fn &optional doc-string)
   (with-temp-buffer
     (funcall mode)
     (insert fixture)
@@ -63,6 +64,14 @@ electric-pair-test-for
             (mapcar #'car bindings)
             (mapcar #'cdr bindings)
           (call-interactively (key-binding `[,last-command-event])))))
+    (when
+        (and doc-string
+             (not
+              (and
+               (equal (buffer-substring-no-properties (point-min) (point-max))
+                      expected-string)
+               (equal (point) expected-point))))
+      (message "\n%s\n" doc-string))
     (should (equal (buffer-substring-no-properties (point-min) (point-max))
                    expected-string))
     (should (equal (point)
@@ -109,14 +118,9 @@ electric-pair-test-for
            (fixture (format "%s%s%s" prefix fixture suffix))
            (expected-string (format "%s%s%s" prefix expected-string suffix))
            (expected-point (+ (length prefix) expected-point))
-           (pos (+ (length prefix) pos)))
-      `(ert-deftest ,(intern (format "electric-pair-%s-at-point-%s-in-%s%s"
-                                     name
-                                     (1+ pos)
-                                     mode
-                                     extra-desc))
-           ()
-         ,(format "Electricity test in a `%s' buffer.\n
+           (pos (+ (length prefix) pos))
+           (doc-string
+            (format "Electricity test in a `%s' buffer.\n
 Start with point at %d in a %d-char-long buffer
 like this one:
 
@@ -143,7 +147,14 @@ electric-pair-test-for
                   char
                   (if (string= fixture expected-string) "stay" "become")
                   (replace-regexp-in-string "\n" "\\\\n" expected-string)
-                  expected-point)
+                  expected-point)))
+      `(ert-deftest ,(intern (format "electric-pair-%s-at-point-%s-in-%s%s"
+                                     name
+                                     (1+ pos)
+                                     mode
+                                     extra-desc))
+           ()
+         ,doc-string
          (electric-pair-test-for ,fixture
                                  ,(1+ pos)
                                  ,char
@@ -151,7 +162,8 @@ electric-pair-test-for
                                  ,expected-point
                                  ',mode
                                  ,bindings
-                                 ,fixture-fn)))))
+                                 ,fixture-fn
+                                 ,doc-string)))))
 
 (cl-defmacro define-electric-pair-test
     (name fixture

-- 
Alan Mackenzie (Nuremberg, Germany).