; Tweak some ERC tests and related utilities

* test/lisp/erc/erc-scenarios-keep-place-indicator.el
(erc-scenarios-keep-place-indicator--follow): Intersperse more
`redisplay' calls to update the indicator's overlay.
* test/lisp/erc/erc-tests.el (erc-tests--assert-printed-in-subprocess):
Wrap CODE form in keyword sentinel.
(erc--find-mode, erc--essential-hook-ordering): Use modified interface.
(erc--find-group--real, erc--find-group/realistic): Rename former to
latter and run in subprocess.
(erc--update-modules/realistic): Redo to run in subprocess instead of
mocking.
* test/lisp/erc/resources/erc-d/erc-d-t.el
(erc-d-t-kill-related-buffers): Don't bother canceling
`erc-server-flood-timer', even in an actual ERC buffer, since
`erc-server-send-queue' first checks whether its BUFFER argument is
still live before sending anything to the process.  Also, don't bother
collecting buffers only to immediately kill them.
* test/lisp/erc/resources/erc-d/erc-d.el (erc-d--filter): Always clear
remainder.  Otherwise, partial emissions from the peer that aren't
terminated by a newline will confuse subsequent processing.
* test/lisp/erc/resources/erc-scenarios-common.el
(erc-scenarios-common--run-in-term): Look for a library called
`erc-tests-compat', which ERC uses in its external CI to provide
compatibility shims of definitions too obscure or unfit for inclusion in
the Compat package on ELPA.
* test/lisp/erc/resources/erc-tests-common.el
(erc-tests-common-kill-buffers): Also kill non-`erc-mode' buffers whose
names match a scheme used by ERC for work buffers.  Allow for the
EXTRA-BUFFERS argument to possibly contain killed and null buffers.

test/lisp/erc/erc-scenarios-keep-place-indicator.el

@@ -79,6 +79,7 @@
         (switch-to-buffer (erc-d-t-wait-for 10 (get-buffer "#spam"))) ; lower
         (other-window 1)
         (switch-to-buffer "#spam") ; upper
+        (redisplay)
         (erc-scenarios-common-say "one")
         (funcall expect 10 "Ay, the heads")
 
@@ -94,6 +95,7 @@
         ;; Lower window is still centered at start.
         (other-window 1)
         (switch-to-buffer "#chan")
+        (redisplay)
         (save-excursion
           (goto-char (window-point))
           (should (looking-back (rx "<alice> tester, welcome!")))
@@ -107,8 +109,10 @@
 
         (other-window 1) ; upper still at indicator, switches first
         (switch-to-buffer "#spam")
+        (redisplay)
         (other-window 1)
         (switch-to-buffer "#spam") ; lower follows, speaks to sync
+        (redisplay)
         (erc-scenarios-common-say "two")
         (funcall expect 10 "<bob> Cause they take")
         (goto-char (point-max))
@@ -116,6 +120,7 @@
         ;; Upper switches back first, finds indicator gone.
         (other-window 1)
         (switch-to-buffer "#chan")
+        (redisplay)
         (save-excursion
           (goto-char (window-point))
           (should (looking-back (rx "<bob> tester, welcome!")))

test/lisp/erc/erc-tests.el

@@ -3729,11 +3729,14 @@ keyword :result."
       (get-buffer-create
        (concat "*" (symbol-name (ert-test-name (ert-running-test))) "*"))
     (unwind-protect
-        (let ((proc (erc-tests-common-create-subprocess code '("-batch") nil)))
+        (let ((proc (erc-tests-common-create-subprocess
+                     `(,@(butlast code) (prin1 (list :result ,@(last code))))
+                     '("-batch") nil)))
           (while (accept-process-output proc 10))
           (goto-char (point-min))
-          (search-forward "(:result " nil t)
-          (unless (equal (ignore-errors (read (current-buffer))) expected)
+          (unless (equal (and (search-forward "(:result " nil t)
+                              (read (current-buffer)))
+                         expected)
             (ert-fail (list "Mismatch"
                             :expected expected
                             :buffer-string (buffer-string)))))
@@ -3755,18 +3758,15 @@ keyword :result."
         (unless (keywordp mod)
           (push (if-let* ((mode (erc--find-mode mod))) mod (list :missing mod))
                 moded)))
-      (prin1 (list :result
-                   (sort moded (lambda (a b)
-                                 (string< (symbol-name a) (symbol-name b)))))))
+      (sort moded (lambda (a b) (string< (symbol-name a) (symbol-name b)))))
    erc-tests--modules))
 
 (ert-deftest erc--essential-hook-ordering ()
   (erc-tests--assert-printed-in-subprocess
    '(progn
       (erc-update-modules)
-      (prin1 (list :result
-                   (list :erc-insert-modify-hook erc-insert-modify-hook
-                         :erc-send-modify-hook erc-send-modify-hook))))
+      (list :erc-insert-modify-hook erc-insert-modify-hook
+            :erc-send-modify-hook erc-send-modify-hook))
 
    '( :erc-insert-modify-hook (erc-controls-highlight ; 0
                                erc-button-add-buttons ; 30
@@ -3798,26 +3798,37 @@ keyword :result."
     (should (eq (erc--find-group 'foo nil) 'erc))
     (should (eq (erc--find-group 'fake 'baz) 'erc-foo))))
 
-(ert-deftest erc--find-group--real ()
-  :tags '(:unstable)
-  (require 'erc-services)
-  (require 'erc-stamp)
-  (require 'erc-sound)
-  (require 'erc-page)
-  (require 'erc-join)
-  (require 'erc-capab)
-  (require 'erc-pcomplete)
-  (should (eq (erc--find-group 'services 'nickserv) 'erc-services))
-  (should (eq (erc--find-group 'stamp 'timestamp) 'erc-stamp))
-  (should (eq (erc--find-group 'sound 'ctcp-sound) 'erc-sound))
-  (should (eq (erc--find-group 'page 'ctcp-page) 'erc-page))
-  (should (eq (erc--find-group 'autojoin) 'erc-autojoin))
-  (should (eq (erc--find-group 'pcomplete 'Completion) 'erc-pcomplete))
-  (should (eq (erc--find-group 'capab-identify) 'erc-capab))
-  (should (eq (erc--find-group 'completion) 'erc-pcomplete))
-  ;; No group specified.
-  (should (eq (erc--find-group 'smiley nil) 'erc))
-  (should (eq (erc--find-group 'unmorse nil) 'erc)))
+(ert-deftest erc--find-group/realistic ()
+  (erc-tests--assert-printed-in-subprocess
+   '(progn
+      (require 'erc-services)
+      (require 'erc-stamp)
+      (require 'erc-sound)
+      (require 'erc-page)
+      (require 'erc-join)
+      (require 'erc-capab)
+      (require 'erc-pcomplete)
+      (list (erc--find-group 'services 'nickserv)
+            (erc--find-group 'stamp 'timestamp)
+            (erc--find-group 'sound 'ctcp-sound)
+            (erc--find-group 'page 'ctcp-page)
+            (erc--find-group 'autojoin)
+            (erc--find-group 'pcomplete 'Completion)
+            (erc--find-group 'completion)
+            (erc--find-group 'capab-identify)
+            ;; No group specified.
+            (erc--find-group 'smiley nil)
+            (erc--find-group 'unmorse nil)))
+   '(erc-services
+     erc-stamp
+     erc-sound
+     erc-page
+     erc-autojoin
+     erc-pcomplete
+     erc-pcomplete
+     erc-capab
+     erc
+     erc)))
 
 (ert-deftest erc--sort-modules ()
   (should (equal (erc--sort-modules '(networks foo fill bar fill stamp bar))
@@ -3920,28 +3931,32 @@ keyword :result."
                         "(req . explicit-feature-lib)")))))))
 
 (ert-deftest erc--update-modules/realistic ()
-  (let ((calls nil)
-        ;; Module `pcomplete' "resolves" to `completion'.
-        (erc-modules '(pcomplete autojoin networks)))
-    (cl-letf (((symbol-function 'require)
-               (lambda (s &rest _) (push (cons 'req s) calls)))
+  (erc-tests--assert-printed-in-subprocess
+   '(progn
+      (require 'ert)
+      (require 'erc)
+      (should (featurep 'erc-networks))
+      (should-not erc-networks-mode)
+      ;; The pcomplete module isn't loaded, and the non-alias form of
+      ;; its command isn't autoloaded, so `erc--find-mode' will do so.
+      (should-not (featurep 'erc-pcomplete))
+      (should-not (intern-soft "erc-pcomplete-mode"))
+      ;; The join module is autoloaded.
+      (should-not (featurep 'erc-join))
+      (should (fboundp 'erc-autojoin-mode))
+      (should-not (boundp 'erc-autojoin-mode))
 
-              ;; Spoof global module detection.
-              ((symbol-function 'custom-variable-p)
-               (lambda (v)
-                 (memq v '(erc-autojoin-mode erc-networks-mode
-                                             erc-completion-mode))))
-              ;; Mock and spy real builtins.
-              ((symbol-function 'erc-autojoin-mode)
-               (lambda (n) (push (cons 'autojoin n) calls)))
-              ((symbol-function 'erc-networks-mode)
-               (lambda (n) (push (cons 'networks n) calls)))
-              ((symbol-function 'erc-completion-mode)
-               (lambda (n) (push (cons 'completion n) calls))))
+      ;; These are all global modules, so no return value is expected.
+      (let ((erc-modules (cons (seq-random-elt '(completion pcomplete))
+                               '(networks autojoin))))
+        (should-not (erc--update-modules erc-modules)))
 
-      (should-not (erc--update-modules erc-modules)) ; no locals
-      (should (equal (nreverse calls)
-                     '((completion . 1) (autojoin . 1) (networks . 1)))))))
+      (list erc-networks-mode
+            (featurep 'erc-pcomplete)
+            (featurep 'erc-join)
+            (symbol-value (intern-soft "erc-pcomplete-mode"))
+            (bound-and-true-p erc-autojoin-mode)))
+   '(t t t t t)))
 
 (ert-deftest erc--merge-local-modes ()
   (cl-letf (((get 'erc-b-mode 'erc-module) 'b)

test/lisp/erc/resources/erc-d/erc-d-t.el

@@ -28,22 +28,20 @@
 
 (defun erc-d-t-kill-related-buffers ()
   "Kill all erc- or erc-d- related buffers."
-  (let (buflist)
-    (dolist (buf (buffer-list))
-      (with-current-buffer buf
-        (when (or erc-d-u--process-buffer
-                  (derived-mode-p 'erc-mode 'erc-dcc-chat-mode))
-          (push buf buflist))))
-    (dolist (buf buflist)
-      (when (and (boundp 'erc-server-flood-timer)
-                 (timerp erc-server-flood-timer))
-        (cancel-timer erc-server-flood-timer))
-      (when-let* ((proc (get-buffer-process buf)))
-        (delete-process proc))
-      (when (buffer-live-p buf)
+  (dolist (buf (buffer-list))
+    (with-current-buffer buf
+      (when (or erc-d-u--process-buffer
+                (derived-mode-p 'erc-mode
+                                'erc-dcc-chat-mode)
+                (string-match (rx bot
+                                  (? " ") "*erc" (in "- ") (+ nonl) "*"
+                                  eot)
+                              (buffer-name)))
+        (when-let* ((proc (get-buffer-process buf)))
+          (delete-process proc))
         (kill-buffer buf))))
-  (while (when-let* ((buf (pop erc-d-u--canned-buffers)))
-           (kill-buffer buf))))
+  (while-let ((buf (pop erc-d-u--canned-buffers)))
+    (kill-buffer buf)))
 
 (defun erc-d-t-silence-around (orig &rest args)
   "Run ORIG function with ARGS silently.

test/lisp/erc/resources/erc-d/erc-d.el

@@ -462,8 +462,7 @@ including line delimiters."
                        (substring string (match-end 0))))
         (erc-d--log process line nil)
         (ring-insert queue (erc-d-i--parse-message line nil))))
-    (when string
-      (setf (process-get process :stashed-input) string))))
+    (setf (process-get process :stashed-input) string)))
 
 ;; Misc process properties:
 ;;

test/lisp/erc/resources/erc-scenarios-common.el

@@ -267,6 +267,10 @@ Dialog resource directories are located by expanding the variable
                               (package-initialize))))
                    (require 'erc)
                    (cl-assert (equal erc-version ,erc-version) t)))
+         ;; Load test-related compat shims too niche for Compat, such as
+         ;; a <31 definition of `ert-with-buffer-selected'.
+         (tcompat (and (featurep 'erc-tests-compat)
+                       (locate-library "erc-tests-compat")))
          ;; Make subprocess terminal bigger than controlling.
          (buf (cl-letf (((symbol-function 'window-screen-lines)
                          (lambda () (car erc-scenarios-common--term-size)))
@@ -277,6 +281,9 @@ Dialog resource directories are located by expanding the variable
                        nil `(,@(or init '("-Q")) "-nw"
                              "-eval" ,(format "%S" setup)
                              "-l" ,file-name
+                             ,@(and tcompat
+                                    (list "-L" (file-name-directory tcompat)
+                                          "-l" tcompat))
                              "-eval" ,(format "%S" cmd)))))
          (proc (get-buffer-process buf))
          (err (lambda ()

test/lisp/erc/resources/erc-tests-common.el

@@ -81,11 +81,18 @@ Assign the result to `erc-server-process' in the current buffer."
         ;; To facilitate automatic testing when a fake-server has already
 	;; been created by an earlier ERT test.
 	(kill-buffer-query-functions nil))
-    (dolist (buf (erc-buffer-list))
-      (kill-buffer buf))
+    (mapc #'kill-buffer
+          (match-buffers
+           `(or ,@(static-if (>= emacs-major-version 30)
+                     '((derived-mode erc-mode erc-dcc-chat-mode))
+                   '((major-mode . erc-mode) (major-mode . erc-dcc-chat-mode)))
+                ,(rx bot (? ?\s) "*erc" (in "- ") (+ nonl) ?* eot))))
     (named-let doit ((buffers extra-buffers))
       (dolist (buf buffers)
-        (if (consp buf) (doit buf) (kill-buffer buf))))))
+        (if (consp buf)
+            (doit buf)
+          (when (buffer-live-p buf)
+            (kill-buffer buf)))))))
 
 (defun erc-tests-common-with-process-input-spy (test-fn)
   "Mock `erc-process-input-line' and call TEST-FN.