Improve autorevert-tests

* doc/misc/trampver.texi:
* lisp/net/trampver.el: Change version to "2.8.1-pre".

* lisp/autorevert.el (auto-revert-mode, auto-revert-tail-mode)
(auto-revert-notify-handler, auto-revert--end-lockout):
Use `auto-revert-buffer'.
(auto-revert-notify-handler): Rearrange setting current buffer.
(auto-revert-handler): Add debug message.  Rearrange check.
Cancel lockout timer if running.

* lisp/net/tramp.el (tramp-barf-if-file-missing)
(with-parsed-tramp-file-name, tramp-skeleton-file-truename):
* lisp/net/tramp-archive.el (with-parsed-tramp-archive-file-name):
* lisp/net/tramp-message.el (tramp-with-demoted-errors):
Fix debug declatation.

* lisp/net/tramp-sh.el (tramp-sh-gio-monitor-process-filter): Do not
prepend remote prefix.

* test/lisp/autorevert-tests.el: Unify file notification libraries
"gio-monitor" and "gvfs-monitor-dir" to "gio".
(top): Set some Tramp related variables.
(auto-revert--timeout): Increase value.
(auto-revert--test-enabled-remote)
(auto-revert-test02-auto-revert-deleted-file): Do not check for
EMACS_HYDRA_CI environment variable.
(auto-revert--wait-for-revert): Fix regexp to search for.
(auto-revert--deftest-remote): Fix debug declatation.  Do not tag
:unstable.
(with-auto-revert-test): Fix debug declatation.  Adapt revert intervals.
(auto-revert-test*): Start with (file-notify-rm-all-watches).  Use
`buffer-string' and `string-match-p'.
(auto-revert-test00-auto-revert-mode): Unlock initial lockout.
(auto-revert-test01-auto-revert-several-files): Rearrange
temporary directory and file settings.
(auto-revert-test02-auto-revert-deleted-file): Adapt debug message.
(auto-revert-test03-auto-revert-tail-mode): Use `with-auto-revert-test'.
(auto-revert-test04-auto-revert-mode-dired):
Use `ert-with-temp-directory'.  Adapt prefix of tmpfile.
(auto-revert-test04-auto-revert-mode-dired)
(auto-revert-test05-global-notify, auto-revert-test06-write-file):
Wait for proper file modification.
(auto-revert-test--instrument-kill-buffer-hook): Fix debug message.
(auto-revert-test07-auto-revert-several-buffers): Use
`with-auto-revert-test.

* test/lisp/filenotify-tests.el: Unify file notification libraries
"gio-monitor" and "gvfs-monitor-dir" to "gio".
(file-notify--deftest-remote): Fix debug declatation.  Do not skip
for "gio".
(file-notify--test-with-actions): Fix debug declatation.

* test/lisp/net/tramp-tests.el (filenotify): Require.
(ert-remote-temporary-file-directory)
(tramp-test41-special-characters, tramp-test42-utf8)
(tramp-test45-asynchronous-requests): Do not check for
EMACS_HYDRA_CI environment variable.
(tramp-test46-file-notifications): New test.

10 files changed, 342 insertions, 206 deletions

diff --git a/doc/misc/trampver.texi b/doc/misc/trampver.texi
index a6e305534aa..bfae103a782 100644
--- a/doc/misc/trampver.texi
+++ b/doc/misc/trampver.texi
@@ -7,7 +7,7 @@
 
 @c In the  Tramp GIT, the version number and the bug report address
 @c are auto-frobbed from configure.ac.
-@set trampver 2.8.0
+@set trampver 2.8.1-pre
 @set trampurl https://www.gnu.org/software/tramp/
 @set tramp-bug-report-address tramp-devel@@gnu.org
 @set emacsver 28.1
diff --git a/lisp/autorevert.el b/lisp/autorevert.el
index 4eaf42da89e..4eb1a0e85ba 100644
--- a/lisp/autorevert.el
+++ b/lisp/autorevert.el
@@ -415,7 +415,7 @@ without being changed in the part that is already in the buffer."
     (auto-revert-remove-current-buffer))
   (auto-revert-set-timer)
   (when auto-revert-mode
-    (auto-revert-buffers)
+    (auto-revert-buffer (current-buffer))
     (setq auto-revert-tail-mode nil)))
 
 
@@ -470,7 +470,7 @@ Use `auto-revert-mode' for changes other than appends!"
            (y-or-n-p "File changed on disk, content may be missing.  \
 Perform a full revert? ")
            ;; Use this (not just revert-buffer) for point-preservation.
-           (auto-revert-buffers))
+           (auto-revert-buffer (current-buffer)))
       ;; else we might reappend our own end when we save
       (add-hook 'before-save-hook (lambda () (auto-revert-tail-mode 0)) nil t)
       (or (local-variable-p 'auto-revert-tail-pos) ; don't lose prior position
@@ -716,9 +716,9 @@ system.")
         (message "auto-revert-notify-handler %S" event))
 
       (when (buffer-live-p buffer)
-        (if (eq action 'stopped)
-            ;; File notification has stopped.  Continue with polling.
-            (with-current-buffer buffer
+        (with-current-buffer buffer
+          (if (eq action 'stopped)
+              ;; File notification has stopped.  Continue with polling.
               (when (or
                      ;; A buffer associated with a file.
                      (and (stringp buffer-file-name)
@@ -730,9 +730,8 @@ system.")
                 (auto-revert-notify-rm-watch)
                 ;; Restart the timer if it wasn't running.
                 (unless auto-revert-timer
-                  (auto-revert-set-timer))))
+                  (auto-revert-set-timer)))
 
-          (with-current-buffer buffer
             (when (or
                    ;; A buffer associated with a file.
                    (and (stringp buffer-file-name)
@@ -761,7 +760,7 @@ system.")
                 ;; Revert it when first entry or it was reverted intervals ago.
                 (when (> (float-time (time-since auto-revert--last-time))
                          auto-revert--lockout-interval)
-                  (auto-revert-handler))))))))))
+                  (auto-revert-buffer buffer))))))))))
 
 (defun auto-revert--end-lockout (buffer)
   "End the lockout period after a notification.
@@ -770,7 +769,7 @@ If the buffer needs to be reverted, do it now."
     (with-current-buffer buffer
       (setq auto-revert--lockout-timer nil)
       (when auto-revert-notify-modified-p
-        (auto-revert-handler)))))
+        (auto-revert-buffer buffer)))))
 
 ;;;###autoload
 (progn
@@ -809,36 +808,37 @@ Run BODY."
 (defun auto-revert-handler ()
   "Revert current buffer, if appropriate.
 This is an internal function used by Auto-Revert Mode."
+  (when auto-revert-debug
+    (message "auto-revert-handler %S" (current-buffer)))
   (let* ((buffer (current-buffer)) size
          ;; Tramp caches the file attributes.  Setting
          ;; `remote-file-name-inhibit-cache' forces Tramp to reread
          ;; the values.
          (remote-file-name-inhibit-cache t)
          (revert
-          (if buffer-file-name
-              (and (or auto-revert-remote-files
-                       (not (file-remote-p buffer-file-name)))
-                   (or (not auto-revert-notify-watch-descriptor)
-                       auto-revert-notify-modified-p)
-                   (not (memq (current-buffer) inhibit-auto-revert-buffers))
-                   (if auto-revert-tail-mode
-                       (and (file-readable-p buffer-file-name)
-                            (/= auto-revert-tail-pos
-                                (setq size
-                                      (file-attribute-size
-                                       (file-attributes buffer-file-name)))))
-                     (funcall (or buffer-stale-function
-                                  #'buffer-stale--default-function)
-                              t)))
-            (and (or auto-revert-mode
-                     global-auto-revert-non-file-buffers)
-                 (not (memq (current-buffer) inhibit-auto-revert-buffers))
-                 (funcall (or buffer-stale-function
-                              #'buffer-stale--default-function)
-                          t))))
+          (and (or auto-revert-remote-files
+                   (not (file-remote-p default-directory)))
+               (or (not auto-revert-notify-watch-descriptor)
+                   auto-revert-notify-modified-p)
+               (not (memq (current-buffer) inhibit-auto-revert-buffers))
+               (if (and buffer-file-name auto-revert-tail-mode)
+                   (and (file-readable-p buffer-file-name)
+                        (/= auto-revert-tail-pos
+                            (setq size
+                                  (file-attribute-size
+                                   (file-attributes buffer-file-name)))))
+                 (and (or auto-revert-mode auto-revert--global-mode)
+                      (funcall (or buffer-stale-function
+                                   #'buffer-stale--default-function)
+                               t)))))
          eob eoblist)
+    (when (timerp auto-revert--lockout-timer)
+      (cancel-timer auto-revert--lockout-timer))
     (setq auto-revert-notify-modified-p nil
-          auto-revert--last-time (current-time))
+          auto-revert--last-time
+          (if revert (current-time) auto-revert--last-time)
+          auto-revert--lockout-timer nil)
+
     (when revert
       (when (and auto-revert-verbose
                  (not (eq revert 'fast)))
diff --git a/lisp/net/tramp-archive.el b/lisp/net/tramp-archive.el
index 0a1c44d3673..3de909911b4 100644
--- a/lisp/net/tramp-archive.el
+++ b/lisp/net/tramp-archive.el
@@ -557,7 +557,7 @@ A variable `foo-archive' (or `archive') will be bound to the
 archive name part of FILENAME, assuming `foo' (or nil) is the
 value of VAR.  OTOH, the variable `foo-hop' (or `hop') won't be
 offered."
-  (declare (debug (form symbolp body))
+  (declare (debug (form symbolp &rest body))
            (indent 2))
   (let ((bindings
          (mapcar
diff --git a/lisp/net/tramp-message.el b/lisp/net/tramp-message.el
index d87c62a4b50..5131e5fced9 100644
--- a/lisp/net/tramp-message.el
+++ b/lisp/net/tramp-message.el
@@ -454,7 +454,7 @@ an input event arrives.  The other arguments are passed to `tramp-error'."
 BODY is executed like wrapped by `with-demoted-errors'.  FORMAT
 is a format-string containing a %-sequence meaning to substitute
 the resulting error message."
-  (declare (indent 2) (debug (symbolp form body)))
+  (declare (indent 2) (debug (symbolp form &rest body)))
   (let ((err (make-symbol "err")))
     `(condition-case-unless-debug ,err
          (progn ,@body)
diff --git a/lisp/net/tramp-sh.el b/lisp/net/tramp-sh.el
index 41a1cdf3409..457c9cf6b0e 100644
--- a/lisp/net/tramp-sh.el
+++ b/lisp/net/tramp-sh.el
@@ -3864,8 +3864,6 @@ Fall back to normal file name handler if no Tramp handler exists."
 (defun tramp-sh-gio-monitor-process-filter (proc string)
   "Read output from \"gio monitor\" and add corresponding `file-notify' events."
   (let ((events (process-get proc 'tramp-events))
-        (remote-prefix
-         (file-remote-p (tramp-get-default-directory (process-buffer proc))))
         (rest-string (process-get proc 'tramp-rest-string))
         pos)
     (when rest-string
@@ -3927,10 +3925,7 @@ Fall back to normal file name handler if no Tramp handler exists."
                  proc
                  (list
                   (intern-soft (match-string 2 string)))
-                 ;; File names are returned as absolute paths.  We
-                 ;; must add the remote prefix.
-                 (concat remote-prefix file)
-                 (when file1 (concat remote-prefix file1)))))
+                 file file1)))
           (setq string (replace-match "" nil nil string))
           ;; Add an Emacs event now.
           ;; `insert-special-event' exists since Emacs 31.
diff --git a/lisp/net/tramp.el b/lisp/net/tramp.el
index d64f6ba37ac..5a19e4be1ae 100644
--- a/lisp/net/tramp.el
+++ b/lisp/net/tramp.el
@@ -2102,7 +2102,7 @@ of `current-buffer'."
   "Execute BODY and return the result.
 In case of an error, raise a `file-missing' error if FILENAME
 does not exist, otherwise propagate the error."
-  (declare (indent 2) (debug (symbolp form body)))
+  (declare (indent 2) (debug (tramp-file-name-p form &rest body)))
   (let ((err (make-symbol "err")))
     `(condition-case ,err
          (let (signal-hook-function) ,@body)
@@ -2141,7 +2141,7 @@ Remaining args are Lisp expressions to be evaluated (inside an implicit
 
 If VAR is nil, then we bind `v' to the structure and `method', `user',
 `domain', `host', `port', `localname', `hop' to the components."
-  (declare (indent 2) (debug (form symbolp body)))
+  (declare (indent 2) (debug (form symbolp &rest body)))
   (let ((bindings
          (mapcar
           (lambda (elem)
@@ -3601,7 +3601,7 @@ BODY is the backend specific code."
 (defmacro tramp-skeleton-file-truename (filename &rest body)
   "Skeleton for `tramp-*-handle-file-truename'.
 BODY is the backend specific code."
-  (declare (indent 1) (debug (form body)))
+  (declare (indent 1) (debug (form &rest body)))
   ;; Preserve trailing "/".
   `(funcall
     (if (directory-name-p ,filename) #'file-name-as-directory #'identity)
diff --git a/lisp/net/trampver.el b/lisp/net/trampver.el
index 65e60c0464a..56e525e8d81 100644
--- a/lisp/net/trampver.el
+++ b/lisp/net/trampver.el
@@ -7,7 +7,7 @@
 ;; Maintainer: Michael Albinus <michael.albinus@gmx.de>
 ;; Keywords: comm, processes
 ;; Package: tramp
-;; Version: 2.8.0
+;; Version: 2.8.1-pre
 ;; Package-Requires: ((emacs "28.1"))
 ;; Package-Type: multi
 ;; URL: https://www.gnu.org/software/tramp/
@@ -40,7 +40,7 @@
 ;; ./configure" to change them.
 
 ;;;###tramp-autoload
-(defconst tramp-version "2.8.0"
+(defconst tramp-version "2.8.1-pre"
   "This version of Tramp.")
 
 ;;;###tramp-autoload
@@ -76,7 +76,7 @@
 ;; Check for Emacs version.
 (let ((x   (if (not (string-version-lessp emacs-version "28.1"))
       "ok"
-    (format "Tramp 2.8.0 is not fit for %s"
+    (format "Tramp 2.8.1-pre is not fit for %s"
             (replace-regexp-in-string "\n" "" (emacs-version))))))
   (unless (string-equal "ok" x) (error "%s" x)))
 
diff --git a/test/lisp/autorevert-tests.el b/test/lisp/autorevert-tests.el
index 4aab58a6f02..9b46ec68b99 100644
--- a/test/lisp/autorevert-tests.el
+++ b/test/lisp/autorevert-tests.el
@@ -37,7 +37,7 @@
 ;; of a respective command.  The first command found is used.  In
 ;; order to use a dedicated one, the environment variable
 ;; $REMOTE_FILE_NOTIFY_LIBRARY shall be set, possible values are
-;; "inotifywait", "gio-monitor" and "gvfs-monitor-dir".
+;; "inotifywait", "gio" and "smb-notify".
 
 ;; Local file-notify libraries are auto-detected during Emacs
 ;; configuration.  This can be changed with a respective configuration
@@ -56,22 +56,33 @@
 (require 'ert-x)
 (require 'autorevert)
 
-(setq auto-revert-debug nil
+(setq auth-source-cache-expiry nil
+      auth-source-save-behavior nil
+      auto-revert-debug nil
       auto-revert-notify-exclude-dir-regexp "nothing-to-be-excluded"
       auto-revert-stop-on-user-input nil
+      ert-temp-file-prefix "auto-revert-test"
+      ert-temp-file-suffix ""
       file-notify-debug nil
-      tramp-verbose 0)
+      password-cache-expiry nil
+      remote-file-name-inhibit-cache nil
+      tramp-allow-unsafe-temporary-files t
+      tramp-cache-read-persistent-data t ;; For auth-sources.
+      tramp-verbose 0
+      ;; When the remote user id is 0, Tramp refuses unsafe temporary files.
+      tramp-allow-unsafe-temporary-files
+      (or tramp-allow-unsafe-temporary-files noninteractive))
 
 (defun auto-revert--timeout ()
   "Time to wait for a message."
-  (+ auto-revert-interval 0.1))
+  (+ auto-revert-interval 1))
 
 (defvar auto-revert--messages nil
   "Used to collect messages issued during a section of a test.")
 
 ;; Filter suppressed remote file-notify libraries.
 (when (stringp (getenv "REMOTE_FILE_NOTIFY_LIBRARY"))
-  (dolist (lib '("inotifywait" "gio-monitor" "gvfs-monitor-dir"))
+  (dolist (lib '("inotifywait" "gio" "smb-notify"))
     (unless (string-equal (getenv "REMOTE_FILE_NOTIFY_LIBRARY") lib)
       (add-to-list 'tramp-connection-properties `(nil ,lib nil)))))
 
@@ -88,7 +99,6 @@ being the result.")
      (cons
       t (ignore-errors
           (and
-           (not (getenv "EMACS_HYDRA_CI"))
            (file-remote-p ert-remote-temporary-file-directory)
            (file-directory-p ert-remote-temporary-file-directory)
            (file-writable-p ert-remote-temporary-file-directory))))))
@@ -100,12 +110,13 @@ being the result.")
 This expects `auto-revert--messages' to be bound by
 `ert-with-message-capture' before calling."
   ;; Remote files do not cooperate well with timers.  So we count ourselves.
-  (let ((ct (current-time)))
+  (let ((ct (current-time))
+        (text-quoting-style 'grave))
     (while (and (< (float-time (time-subtract nil ct))
                    (auto-revert--timeout))
-                (null (string-match
-                       (format-message
-                        "Reverting buffer `%s'" (buffer-name buffer))
+                (null (string-match-p
+                       (rx bol "Reverting buffer `"
+                           (literal (buffer-name buffer)) "'" eol)
                        (or auto-revert--messages ""))))
       (if (and (or file-notify--library
                    (file-remote-p temporary-file-directory))
@@ -115,10 +126,10 @@ This expects `auto-revert--messages' to be bound by
 
 (defmacro auto-revert--deftest-remote (test docstring)
   "Define ert `TEST-remote' for remote files."
-  (declare (indent 1))
+  (declare (indent 1) (debug (symbolp stringp)))
   `(ert-deftest ,(intern (concat (symbol-name test) "-remote")) ()
      ,docstring
-     :tags '(:expensive-test :unstable)
+     :tags '(:expensive-test)
      (let ((temporary-file-directory
             ert-remote-temporary-file-directory)
            (auto-revert-remote-files t)
@@ -132,12 +143,14 @@ This expects `auto-revert--messages' to be bound by
          (error (message "%s" err) (signal (car err) (cdr err)))))))
 
 (defmacro with-auto-revert-test (&rest body)
+  (declare (debug t))
   `(let ((auto-revert-interval-orig auto-revert-interval)
          (auto-revert--lockout-interval-orig auto-revert--lockout-interval))
      (unwind-protect
          (progn
-           (customize-set-variable 'auto-revert-interval 0.1)
-           (setq auto-revert--lockout-interval 0.05)
+           (unless (file-remote-p temporary-file-directory)
+             (customize-set-variable 'auto-revert-interval 0.1)
+             (setq auto-revert--lockout-interval 0.05))
            ,@body)
        (customize-set-variable 'auto-revert-interval auto-revert-interval-orig)
        (setq auto-revert--lockout-interval auto-revert--lockout-interval-orig))))
@@ -148,6 +161,8 @@ This expects `auto-revert--messages' to be bound by
 
 (ert-deftest auto-revert-test00-auto-revert-mode ()
   "Check autorevert for a file."
+  (file-notify-rm-all-watches)
+
   ;; `auto-revert-buffers' runs every 5".  And we must wait, until the
   ;; file has been reverted.
   (with-auto-revert-test
@@ -160,18 +175,30 @@ This expects `auto-revert--messages' to be bound by
              (setq buf (find-file-noselect tmpfile))
              (with-current-buffer buf
                (ert-with-message-capture auto-revert--messages
-                 (should (string-equal (buffer-string) "any text"))
+                 (should
+                  (string-equal
+                   (substring-no-properties (buffer-string)) "any text"))
                  ;; `buffer-stale--default-function' checks for
                  ;; `verify-visited-file-modtime'.  We must ensure that it
-                 ;; returns nil.
+                 ;; returns nil.  We also clean up.
                  (auto-revert-mode 1)
                  (should auto-revert-mode)
+                 ;; There was already an initial call of
+                 ;; `auto-revert-handler', which locks file
+                 ;; notification.  Reset this lock.
+                 (setq auto-revert--last-time 0)
+                 (auto-revert-test--wait-for
+                  (lambda () (null auto-revert--lockout-timer))
+                  (auto-revert--timeout))
 
-                 (auto-revert-tests--write-file "another text" tmpfile (pop times))
+                 (auto-revert-tests--write-file
+                  "another text" tmpfile (pop times))
 
                  ;; Check, that the buffer has been reverted.
                  (auto-revert--wait-for-revert buf))
-               (should (string-match "another text" (buffer-string)))
+               (should
+                (string-match-p
+                 "another text" (substring-no-properties (buffer-string))))
 
                ;; When the buffer is modified, it shall not be reverted.
                (ert-with-message-capture auto-revert--messages
@@ -180,7 +207,9 @@ This expects `auto-revert--messages' to be bound by
 
                  ;; Check, that the buffer hasn't been reverted.
                  (auto-revert--wait-for-revert buf))
-               (should-not (string-match "any text" (buffer-string)))))
+               (should-not
+                (string-match-p
+                 "any text" (substring-no-properties (buffer-string))))))
 
          ;; Exit.
          (ignore-errors
@@ -194,27 +223,35 @@ This expects `auto-revert--messages' to be bound by
 (ert-deftest auto-revert-test01-auto-revert-several-files ()
   "Check autorevert for several files at once."
   (skip-unless (executable-find "cp" (file-remote-p temporary-file-directory)))
+  (file-notify-rm-all-watches)
 
-  (ert-with-temp-directory tmpdir1
-    (ert-with-temp-directory tmpdir2
-      (ert-with-temp-file tmpfile1
-        :prefix (expand-file-name "auto-revert-test" tmpdir1)
-        (ert-with-temp-file tmpfile2
-          :prefix (expand-file-name "auto-revert-test" tmpdir1)
-          (with-auto-revert-test
-           (let* ((cp (executable-find "cp" (file-remote-p temporary-file-directory)))
+  (with-auto-revert-test
+   (ert-with-temp-directory tmpdir1
+     :prefix "auto-revert-test-parent"
+     (ert-with-temp-directory tmpdir2
+       :prefix "auto-revert-test-parent"
+       (ert-with-temp-file tmpfile1
+         :prefix (expand-file-name "auto-revert-test" tmpdir1)
+         (ert-with-temp-file tmpfile2
+           :prefix (expand-file-name "auto-revert-test" tmpdir1)
+           (let* ((cp (executable-find
+                       "cp" (file-remote-p temporary-file-directory)))
                   (times '(120 60 30 15))
                   buf1 buf2)
              (unwind-protect
                  (ert-with-message-capture auto-revert--messages
-                   (auto-revert-tests--write-file "any text" tmpfile1 (pop times))
+                   (auto-revert-tests--write-file
+                    "any text" tmpfile1 (pop times))
                    (setq buf1 (find-file-noselect tmpfile1))
-                   (auto-revert-tests--write-file "any text" tmpfile2 (pop times))
+                   (auto-revert-tests--write-file
+                    "any text" tmpfile2 (pop times))
                    (setq buf2 (find-file-noselect tmpfile2))
 
                    (dolist (buf (list buf1 buf2))
                      (with-current-buffer buf
-                       (should (string-equal (buffer-string) "any text"))
+                       (should
+                        (string-equal
+                         (substring-no-properties (buffer-string)) "any text"))
                        ;; `buffer-stale--default-function' checks for
                        ;; `verify-visited-file-modtime'.  We must ensure that
                        ;; it returns nil.
@@ -236,14 +273,17 @@ This expects `auto-revert--messages' to be bound by
                    ;; The following shell command is not portable on all
                    ;; platforms, unfortunately.
                    (shell-command
-                    (format "%s -f %s/* %s"
-                            cp (file-local-name tmpdir2) (file-local-name tmpdir1)))
+                    (format "%s -f %s/* %s" cp
+                            (file-local-name tmpdir2) (file-local-name tmpdir1)))
 
                    ;; Check, that the buffers have been reverted.
                    (dolist (buf (list buf1 buf2))
                      (with-current-buffer buf
                        (auto-revert--wait-for-revert buf)
-                       (should (string-match "another text" (buffer-string))))))
+                       (should
+                        (string-match-p
+                         "another text"
+                         (substring-no-properties (buffer-string)))))))
 
                ;; Exit.
                (ignore-errors
@@ -257,16 +297,11 @@ This expects `auto-revert--messages' to be bound by
 ;; This is inspired by Bug#23276.
 (ert-deftest auto-revert-test02-auto-revert-deleted-file ()
   "Check autorevert for a deleted file."
-  ;; Repeated unpredictable failures, bug#32645.
-  :tags '(:unstable)
-  ;; Unlikely to be hydra-specific?
-  ;; (skip-when (getenv "EMACS_HYDRA_CI"))
+  (file-notify-rm-all-watches)
+
   (with-auto-revert-test
    (ert-with-temp-file tmpfile
-     (let (;; Try to catch bug#32645.
-           (auto-revert-debug (getenv "EMACS_HYDRA_CI"))
-           (file-notify-debug (getenv "EMACS_HYDRA_CI"))
-           (times '(120 60 30 15))
+     (let ((times '(120 60 30 15))
            buf desc)
        (unwind-protect
            (progn
@@ -275,7 +310,9 @@ This expects `auto-revert--messages' to be bound by
              (with-current-buffer buf
                (should-not
                 (file-notify-valid-p auto-revert-notify-watch-descriptor))
-               (should (string-equal (buffer-string) "any text"))
+               (should
+                (string-equal
+                 (substring-no-properties (buffer-string)) "any text"))
                ;; `buffer-stale--default-function' checks for
                ;; `verify-visited-file-modtime'.  We must ensure that
                ;; it returns nil.
@@ -289,51 +326,47 @@ This expects `auto-revert--messages' to be bound by
                 'before-revert-hook
                 (lambda ()
                   (when auto-revert-debug
-                    (message "%s deleted" buffer-file-name))
+                    (message "before-revert-hook %s deleted" buffer-file-name))
                   (delete-file buffer-file-name))
                 nil t)
 
                (ert-with-message-capture auto-revert--messages
-                 (auto-revert-tests--write-file "another text" tmpfile (pop times))
+                 (auto-revert-tests--write-file
+                  "another text" tmpfile (pop times))
                  (should (eq desc auto-revert-notify-watch-descriptor))
                  (auto-revert--wait-for-revert buf))
                ;; Check, that the buffer hasn't been reverted.  File
                ;; notification should be disabled, falling back to
                ;; polling.
-               (should (string-match "any text" (buffer-string)))
-               ;; With w32notify, and on emba, the `stopped' events are not sent.
-               (or (eq file-notify--library 'w32notify)
-                   (getenv "EMACS_EMBA_CI")
-                   (should-not
-                    ;; The auto-revert timer is wont to establish a new
-                    ;; watch soon after the previous descriptor is
-                    ;; destroyed, which not unnaturally interferes with
-                    ;; our testing for its destruction, since descriptor
-                    ;; IDs are reused.  Therefore, test the identity of
-                    ;; the previous descriptor, not just its validity.
-                    (and (eq desc auto-revert-notify-watch-descriptor)
-                         (file-notify-valid-p auto-revert-notify-watch-descriptor))))
+               (should
+                (string-match-p
+                 "any text" (substring-no-properties (buffer-string))))
 
                ;; Once the file has been recreated, the buffer shall be
                ;; reverted.
                (kill-local-variable 'before-revert-hook)
                (ert-with-message-capture auto-revert--messages
-                 (auto-revert-tests--write-file "another text" tmpfile (pop times))
+                 (auto-revert-tests--write-file
+                  "another text" tmpfile (pop times))
                  (auto-revert--wait-for-revert buf))
                ;; Check, that the buffer has been reverted.
-               (should (string-match "another text" (buffer-string)))
+               (should
+                (string-match-p
+                 "another text" (substring-no-properties (buffer-string))))
                ;; When file notification is used, it must be reenabled
                ;; after recreation of the file.  We cannot expect that
                ;; the descriptor is the same, so we just check the
                ;; existence.
-               (should (eq (null desc) (null auto-revert-notify-watch-descriptor)))
+               (should
+                (eq (null desc) (null auto-revert-notify-watch-descriptor)))
 
                ;; An empty file shall still be reverted.
                (ert-with-message-capture auto-revert--messages
                  (auto-revert-tests--write-file "" tmpfile (pop times))
                  (auto-revert--wait-for-revert buf))
                ;; Check, that the buffer has been reverted.
-               (should (string-equal "" (buffer-string)))))
+               (should
+                (string-equal "" (substring-no-properties (buffer-string))))))
 
          ;; Exit.
          (ignore-errors
@@ -345,6 +378,9 @@ This expects `auto-revert--messages' to be bound by
 
 (ert-deftest auto-revert-test03-auto-revert-tail-mode ()
   "Check autorevert tail mode."
+  (file-notify-rm-all-watches)
+
+  (with-auto-revert-test
   ;; `auto-revert-buffers' runs every 5".  And we must wait, until the
   ;; file has been reverted.
   (ert-with-temp-file tmpfile
@@ -365,69 +401,90 @@ This expects `auto-revert--messages' to be bound by
               (set-buffer-modified-p nil)
 
               ;; Modify file.
-              (auto-revert-tests--write-file "another text" tmpfile (pop times) 'append)
+              (auto-revert-tests--write-file
+               "another text" tmpfile (pop times) 'append)
 
               ;; Check, that the buffer has been reverted.
               (auto-revert--wait-for-revert buf)
               (should
-               (string-match "modified text\nanother text" (buffer-string)))))
+               (string-match-p
+                "modified text\nanother text"
+                (substring-no-properties (buffer-string))))))
 
         ;; Exit.
-        (ignore-errors (kill-buffer buf))))))
+        (ignore-errors (kill-buffer buf)))))))
 
 (auto-revert--deftest-remote auto-revert-test03-auto-revert-tail-mode
   "Check remote autorevert tail mode.")
 
 (ert-deftest auto-revert-test04-auto-revert-mode-dired ()
   "Check autorevert for dired."
+  (file-notify-rm-all-watches)
+
   ;; `auto-revert-buffers' runs every 5".  And we must wait, until the
   ;; file has been reverted.
   (with-auto-revert-test
-   (ert-with-temp-file tmpfile
-     (let* ((name (file-name-nondirectory tmpfile))
-            (times '(30))
-            buf)
-       (unwind-protect
-           (progn
-             (setq buf (dired-noselect temporary-file-directory))
-             (with-current-buffer buf
-               ;; `buffer-stale--default-function' checks for
-               ;; `verify-visited-file-modtime'.  We must ensure that it
-               ;; returns nil.
-               (auto-revert-mode 1)
-               (should auto-revert-mode)
-               (should
-                (string-match name (substring-no-properties (buffer-string))))
-               ;; If we don't sleep for a while, this test fails on
-               ;; MS-Windows.
-               (if (eq system-type 'windows-nt)
-                   (sleep-for 0.5))
-
-               (ert-with-message-capture auto-revert--messages
-                 ;; Delete file.
-                 (delete-file tmpfile)
-                 (auto-revert--wait-for-revert buf))
-               (if (eq system-type 'windows-nt)
-                   (sleep-for 1))
-               ;; Check, that the buffer has been reverted.
-               (should-not
-                (string-match name (substring-no-properties (buffer-string))))
-
-               (ert-with-message-capture auto-revert--messages
-                 ;; Make dired buffer modified.  Check, that the buffer has
-                 ;; been still reverted.
-                 (set-buffer-modified-p t)
-                 (auto-revert-tests--write-file "any text" tmpfile (pop times))
+   (ert-with-temp-directory tmpdir
+     :prefix "auto-revert-test-parent"
+     (ert-with-temp-file tmpfile
+       :prefix (expand-file-name "auto-revert-test" tmpdir)
+       (let* ((name (file-name-nondirectory tmpfile))
+              (times '(30))
+              buf)
+         (unwind-protect
+             (progn
+               (setq buf (dired-noselect tmpdir))
+               (with-current-buffer buf
+                 ;; `buffer-stale--default-function' checks for
+                 ;; `verify-visited-file-modtime'.  We must ensure that
+                 ;; it returns nil.
+                 (auto-revert-mode 1)
+                 (should auto-revert-mode)
+                 (should
+                  (string-match-p
+                   (rx bow (literal name) eow)
+                   (substring-no-properties (buffer-string))))
+                 ;; If we don't sleep for a while, this test fails on
+                 ;; MS-Windows.
+                 (if (eq system-type 'windows-nt)
+                     (sleep-for 0.5))
+
+                 ;; File stamps of remote files have an accuracy of 1
+                 ;; second.  Wait a little bit.
+                 (when (file-remote-p tmpfile)
+                   (sleep-for (auto-revert--timeout)))
+                 (ert-with-message-capture auto-revert--messages
+                   ;; Delete file.
+                   (delete-file tmpfile)
+                   (auto-revert--wait-for-revert buf))
+                 (if (eq system-type 'windows-nt)
+                     (sleep-for 1))
+                 ;; Check, that the buffer has been reverted.
+                 (should-not
+                  (string-match-p
+                   (rx bow (literal name) eow)
+                   (substring-no-properties (buffer-string))))
+
+                 ;; File stamps of remote files have an accuracy of 1
+                 ;; second.  Wait a little bit.
+                 (when (file-remote-p tmpfile)
+                   (sleep-for (auto-revert--timeout)))
+                 (ert-with-message-capture auto-revert--messages
+                   ;; Make dired buffer modified.  Check, that the
+                   ;; buffer has been still reverted.
+                   (set-buffer-modified-p t)
+                   (auto-revert-tests--write-file "any text" tmpfile (pop times))
+                   (auto-revert--wait-for-revert buf))
+                 ;; Check, that the buffer has been reverted.
+                 (should
+                  (string-match-p
+                   (rx bow (literal name) eow)
+                   (substring-no-properties (buffer-string))))))
 
-                 (auto-revert--wait-for-revert buf))
-               ;; Check, that the buffer has been reverted.
-               (should
-                (string-match name (substring-no-properties (buffer-string))))))
-
-         ;; Exit.
-         (ignore-errors
-           (with-current-buffer buf (set-buffer-modified-p nil))
-           (kill-buffer buf)))))))
+           ;; Exit.
+           (ignore-errors
+             (with-current-buffer buf (set-buffer-modified-p nil))
+             (kill-buffer buf))))))))
 
 (auto-revert--deftest-remote auto-revert-test04-auto-revert-mode-dired
   "Check remote autorevert for dired.")
@@ -439,7 +496,7 @@ This expects `auto-revert--messages' to be bound by
 (defun auto-revert-test--buffer-string (buffer)
   "Contents of BUFFER as a string."
   (with-current-buffer buffer
-    (buffer-string)))
+    (substring-no-properties (buffer-string))))
 
 (defun auto-revert-test--wait-for (pred max-wait)
   "Wait until PRED is true, or MAX-WAIT seconds elapsed."
@@ -462,13 +519,15 @@ This expects `auto-revert--messages' to be bound by
        'kill-buffer-hook
        (lambda ()
          (message
-          "%s killed\n%s" (current-buffer) (with-output-to-string (backtrace))))
+          "%S killed\n%s" (current-buffer) (with-output-to-string (backtrace))))
        nil 'local))))
 
 (ert-deftest auto-revert-test05-global-notify ()
   "Test `global-auto-revert-mode' without polling."
   (skip-unless (or file-notify--library
                    (file-remote-p temporary-file-directory)))
+  (file-notify-rm-all-watches)
+
   (with-auto-revert-test
    (ert-with-temp-file file-1
      (ert-with-temp-file file-2
@@ -484,8 +543,13 @@ This expects `auto-revert--messages' to be bound by
                  (auto-revert-test--instrument-kill-buffer-hook buf-1)
                  (setq buf-2 (find-file-noselect file-2))
                  (auto-revert-test--instrument-kill-buffer-hook buf-2)
+                 ;; File stamps of remote files have an accuracy of 1
+                 ;; second.  Wait a little bit.
+                 (when (file-remote-p file-1)
+                   (sleep-for (auto-revert--timeout)))
                  (auto-revert-test--write-file "1-a" file-1)
-                 (should (equal (auto-revert-test--buffer-string buf-1) ""))
+                 (should
+                  (string-equal (auto-revert-test--buffer-string buf-1) ""))
 
                  (global-auto-revert-mode 1) ; Turn it on.
 
@@ -494,15 +558,20 @@ This expects `auto-revert--messages' to be bound by
                  (should (buffer-local-value
                           'auto-revert-notify-watch-descriptor buf-2))
 
+                 ;; Allow for some time to handle notification events.
+                 (auto-revert-test--wait-for-buffer-text
+                  buf-1 "1-a" (auto-revert--timeout))
                  ;; buf-1 should have been reverted immediately when the mode
                  ;; was enabled.
-                 (should (equal (auto-revert-test--buffer-string buf-1) "1-a"))
+                 (should
+                  (string-equal (auto-revert-test--buffer-string buf-1) "1-a"))
 
                  ;; Alter a file.
                  (auto-revert-test--write-file "2-a" file-2)
                  ;; Allow for some time to handle notification events.
                  (auto-revert-test--wait-for-buffer-text buf-2 "2-a" 1)
-                 (should (equal (auto-revert-test--buffer-string buf-2) "2-a"))
+                 (should
+                  (string-equal (auto-revert-test--buffer-string buf-2) "2-a"))
 
                  ;; Visit a file, and modify it on disk.
                  (setq buf-3 (find-file-noselect file-3))
@@ -517,11 +586,13 @@ This expects `auto-revert--messages' to be bound by
                           'auto-revert-notify-watch-descriptor buf-3))
                  (auto-revert-test--write-file "3-a" file-3)
                  (auto-revert-test--wait-for-buffer-text buf-3 "3-a" 1)
-                 (should (equal (auto-revert-test--buffer-string buf-3) "3-a"))
+                 (should
+                  (string-equal (auto-revert-test--buffer-string buf-3) "3-a"))
 
                  ;; Delete a visited file, and re-create it with new contents.
                  (delete-file file-1)
-                 (should (equal (auto-revert-test--buffer-string buf-1) "1-a"))
+                 (should
+                  (string-equal (auto-revert-test--buffer-string buf-1) "1-a"))
                  (auto-revert-test--write-file "1-b" file-1)
                  ;; Since the file is deleted, it needs at least
                  ;; `auto-revert-interval' to recognize the new file,
@@ -531,10 +602,12 @@ This expects `auto-revert--messages' to be bound by
                  (should (buffer-local-value
                           'auto-revert-notify-watch-descriptor buf-1))
 
-                 ;; Write a buffer to a new file, then modify the new file on disk.
+                 ;; Write a buffer to a new file, then modify the new
+                 ;; file on disk.
                  (with-current-buffer buf-2
                    (write-file file-2b))
-                 (should (equal (auto-revert-test--buffer-string buf-2) "2-a"))
+                 (should
+                  (string-equal (auto-revert-test--buffer-string buf-2) "2-a"))
                  (auto-revert-test--write-file "2-b" file-2b)
                  (auto-revert-test--wait-for-buffer-text
                   buf-2 "2-b" (auto-revert--timeout))
@@ -557,6 +630,8 @@ This expects `auto-revert--messages' to be bound by
   "Verify that notification follows `write-file' correctly."
   (skip-unless (or file-notify--library
                    (file-remote-p temporary-file-directory)))
+  (file-notify-rm-all-watches)
+
   (with-auto-revert-test
    (ert-with-temp-file file-1
      (let* ((auto-revert-use-notify t)
@@ -574,10 +649,15 @@ This expects `auto-revert--messages' to be bound by
                (insert "B")
                (write-file file-2)
 
+               ;; File stamps of remote files have an accuracy of 1
+               ;; second.  Wait a little bit.
+               (when (file-remote-p file-1)
+                 (sleep-for (auto-revert--timeout)))
                (auto-revert-test--write-file "C" file-2)
                (auto-revert-test--wait-for-buffer-text
                 buf "C" (auto-revert--timeout))
-               (should (equal (buffer-string) "C"))))
+               (should
+                (string-equal (substring-no-properties (buffer-string)) "C"))))
 
          ;; Clean up.
          (ignore-errors (kill-buffer buf))
@@ -591,7 +671,9 @@ This expects `auto-revert--messages' to be bound by
   "Check autorevert for several buffers visiting the same file."
   (skip-unless (or file-notify--library
                    (file-remote-p temporary-file-directory)))
-  ;; (with-auto-revert-test
+  (file-notify-rm-all-watches)
+
+  (with-auto-revert-test
   (ert-with-temp-file tmpfile
     (let ((auto-revert-use-notify t)
           (times '(120 60 30 15))
@@ -604,7 +686,9 @@ This expects `auto-revert--messages' to be bound by
             (auto-revert-tests--write-file "any text" tmpfile (pop times))
             (push (find-file-noselect tmpfile) buffers)
             (with-current-buffer (car buffers)
-              (should (string-equal (buffer-string) "any text"))
+              (should
+               (string-equal
+                (substring-no-properties (buffer-string)) "any text"))
               ;; `buffer-stale--default-function' checks for
               ;; `verify-visited-file-modtime'.  We must ensure that
               ;; it returns nil.
@@ -622,7 +706,9 @@ This expects `auto-revert--messages' to be bound by
             (setq buffers (nreverse buffers))
             (dolist (buf buffers)
               (with-current-buffer buf
-                (should (string-equal (buffer-string) "any text"))
+                (should
+                 (string-equal
+                  (substring-no-properties (buffer-string)) "any text"))
                 (if (string-suffix-p "-nil" (buffer-name buf))
                     (should-not auto-revert-mode)
                   (should auto-revert-mode))))
@@ -632,7 +718,9 @@ This expects `auto-revert--messages' to be bound by
             (auto-revert--wait-for-revert (car buffers))
             (dolist (buf buffers)
               (with-current-buffer buf
-                (should (string-equal (buffer-string) "another text"))))
+                (should
+                 (string-equal
+                  (substring-no-properties (buffer-string)) "another text"))))
 
             ;; Disabling autorevert in an indirect buffer does not
             ;; disable autorevert in the corresponding base buffer.
@@ -677,7 +765,9 @@ This expects `auto-revert--messages' to be bound by
             (dolist (buf buffers)
               (with-current-buffer buf
                 (insert-file-contents tmpfile 'visit)
-                (should (string-equal (buffer-string) "any text"))
+                (should
+                 (string-equal
+                  (substring-no-properties (buffer-string)) "any text"))
                 (auto-revert-mode 1)
                 (should auto-revert-mode)))
 
@@ -686,19 +776,23 @@ This expects `auto-revert--messages' to be bound by
             (dolist (buf buffers)
               (auto-revert--wait-for-revert buf)
               (with-current-buffer buf
-                (should (string-equal (buffer-string) "another text")))))
+                (should
+                 (string-equal
+                  (substring-no-properties (buffer-string)) "another text")))))
 
         ;; Exit.
         (ignore-errors
           (dolist (buf buffers)
             (with-current-buffer buf (set-buffer-modified-p nil))
-            (kill-buffer buf)))))));)
+            (kill-buffer buf))))))))
 
 (auto-revert--deftest-remote auto-revert-test07-auto-revert-several-buffers
   "Check autorevert for several buffers visiting the same remote file.")
 
 (ert-deftest auto-revert-test08-auto-revert-inhibit-auto-revert ()
   "Check the power of `inhibit-auto-revert'."
+  (file-notify-rm-all-watches)
+
   ;; `auto-revert-buffers' runs every 5".  And we must wait, until the
   ;; file has been reverted.
   (with-auto-revert-test
@@ -715,14 +809,19 @@ This expects `auto-revert--messages' to be bound by
                    (auto-revert-mode 1)
                    (should auto-revert-mode)
 
-                   (auto-revert-tests--write-file "another text" tmpfile (pop times))
+                   (auto-revert-tests--write-file
+                    "another text" tmpfile (pop times))
                    ;; Check, that the buffer hasn't been reverted.
                    (auto-revert--wait-for-revert buf)
-                   (should-not (string-match "another text" (buffer-string))))
+                   (should-not
+                    (string-match-p
+                     "another text" (substring-no-properties (buffer-string)))))
 
                  ;; Check, that the buffer has been reverted.
                  (auto-revert--wait-for-revert buf)
-                 (should (string-match "another text" (buffer-string))))))
+                 (should
+                  (string-match-p
+                   "another text" (substring-no-properties (buffer-string)))))))
 
          ;; Exit.
          (ignore-errors
diff --git a/test/lisp/filenotify-tests.el b/test/lisp/filenotify-tests.el
index 1a041b0c46c..506d79ecfb3 100644
--- a/test/lisp/filenotify-tests.el
+++ b/test/lisp/filenotify-tests.el
@@ -33,11 +33,11 @@
 ;; remote host, set this environment variable to "/dev/null" or
 ;; whatever is appropriate on your system.
 
-;; For the remote file-notify library, Tramp checks for the existence
-;; of a respective command.  The first command found is used.  In
-;; order to use a dedicated one, the environment variable
+;; For the remote file-notify library, Tramp checks for the existence of
+;; a respective command.  The first command found is used.  In order to
+;; use a dedicated one, the environment variable
 ;; $REMOTE_FILE_NOTIFY_LIBRARY shall be set, possible values are
-;; "inotifywait", "gio-monitor", "gvfs-monitor-dir", and "smb-notify".
+;; "inotifywait", "gio", and "smb-notify".
 
 ;; Local file-notify libraries are auto-detected during Emacs
 ;; configuration.  This can be changed with a respective configuration
@@ -58,7 +58,7 @@
 
 ;; Filter suppressed remote file-notify libraries.
 (when (stringp (getenv "REMOTE_FILE_NOTIFY_LIBRARY"))
-  (dolist (lib '("inotifywait" "gio-monitor" "gvfs-monitor-dir" "smb-notify"))
+  (dolist (lib '("inotifywait" "gio" "smb-notify"))
     (unless (string-equal (getenv "REMOTE_FILE_NOTIFY_LIBRARY") lib)
       (add-to-list 'tramp-connection-properties `(nil ,lib nil)))))
 
@@ -238,9 +238,9 @@ remote host, or nil."
 
 (defun file-notify--test-monitor ()
   "The used monitor for the test, as a symbol.
-This returns only for (local) gfilenotify or (remote) gio library;
-otherwise it is nil.  `file-notify--test-desc' must be a valid
-watch descriptor."
+This returns only for (local) gfilenotify, (remote) gio or (remote)
+smb-notify libraries; otherwise it is nil.  `file-notify--test-desc'
+must be a valid watch descriptor."
   ;; We cache the result, because after `file-notify-rm-watch',
   ;; `gfile-monitor-name' does not return a proper result anymore.
   ;; But we still need this information.  So far, we know the monitors
@@ -277,7 +277,7 @@ watch descriptor."
 (defmacro file-notify--deftest-remote (test docstring &optional unstable)
   "Define ert `TEST-remote' for remote files.
 If UNSTABLE is non-nil, the test is tagged as `:unstable'."
-  (declare (indent 1))
+  (declare (indent 1) (debug (symbolp stringp &optional form)))
   `(ert-deftest ,(intern (concat (symbol-name test) "-remote")) ()
      ,docstring
      :tags (if ,unstable '(:expensive-test :unstable) '(:expensive-test))
@@ -285,9 +285,6 @@ If UNSTABLE is non-nil, the test is tagged as `:unstable'."
             (ert-test (ert-get-test ',test))
             vc-handled-backends)
        (skip-unless (file-notify--test-remote-enabled))
-       ;; These tests do not work for remote gio/GInotifyFileMonitor.
-       ;; Needs further investigation.
-       (skip-when (string-equal (file-notify--test-library) "gio"))
        (tramp-cleanup-connection
         (tramp-dissect-file-name temporary-file-directory) t 'keep-password)
        (file-notify--test-cleanup)
@@ -623,7 +620,7 @@ just an indicator for comparison.
 
 Don't wait longer than timeout seconds for the actions to be
 delivered."
-  (declare (indent 1) (debug (form body)))
+  (declare (indent 1) (debug (form &rest body)))
   `(let* ((actions (if (consp (car ,actions)) ,actions (list ,actions)))
           (max-length
            (apply
@@ -1615,7 +1612,8 @@ the file watch."
   "Check that file notification does not use too many resources."
   :tags '(:expensive-test)
   (skip-unless (file-notify--test-local-enabled))
-  ;; This test is intended for kqueue only.
+  ;; This test is intended for kqueue only.  We cannot check for
+  ;; GKqueueFileMonitor, because `file-notify--test-desc' is not set yet.
   (skip-unless (string-equal (file-notify--test-library) "kqueue"))
 
   (should
diff --git a/test/lisp/net/tramp-tests.el b/test/lisp/net/tramp-tests.el
index f67a33467de..8ac1d3e5a06 100644
--- a/test/lisp/net/tramp-tests.el
+++ b/test/lisp/net/tramp-tests.el
@@ -45,8 +45,8 @@
 ;; might be too heavy.  Setting $REMOTE_PARALLEL_PROCESSES to a proper
 ;; value less than 10 could help.
 
-;; This test suite obeys the environment variables $EMACS_HYDRA_CI and
-;; $EMACS_EMBA_CI, used on the Emacs CI/CD platforms.
+;; This test suite obeys the environment variable $EMACS_EMBA_CI, used
+;; on the Emacs CI/CD platforms.
 
 ;; The following test tags are used: `:expensive-test',
 ;; `:tramp-asynchronous-processes' and `:unstable'.
@@ -60,6 +60,7 @@
 (require 'dired-aux)
 (require 'tramp)
 (require 'ert-x)
+(require 'filenotify)
 (require 'tar-mode)
 (require 'trace)
 (require 'vc)
@@ -121,11 +122,7 @@
           (unless (and (null noninteractive) (file-directory-p "~/"))
             (setenv "HOME" temporary-file-directory))
           (format "/mock::%s" temporary-file-directory)))
-      "Temporary directory for remote file tests.")
-
-    ;; This should happen on hydra only.
-    (when (getenv "EMACS_HYDRA_CI")
-      (add-to-list 'tramp-remote-path 'tramp-own-remote-path))))
+      "Temporary directory for remote file tests.")))
 
 ;; Beautify batch mode.
 (when noninteractive
@@ -2436,8 +2433,7 @@ This checks also `file-name-as-directory', `file-name-directory',
   ;; Bug#10085.
   (when (tramp--test-enabled) ;; Packages like tramp-gvfs.el might be disabled.
     (dolist (non-essential '(nil t))
-      ;; We must clear `tramp-default-method'.  On hydra, it is "ftp",
-      ;; which ruins the tests.
+      ;; We must clear `tramp-default-method'.
       (let ((tramp-default-method
              (file-remote-p ert-remote-temporary-file-directory 'method))
             (host-port
@@ -5222,7 +5218,7 @@ This tests also `make-symbolic-link', `file-truename' and `add-name-to-file'."
       (unwind-protect
           (progn
             ;; We cannot use "/bin/true" and "/bin/false"; those paths
-            ;; do not exist on hydra and on MS Windows.
+            ;; do not exist on MS Windows.
             (should (zerop (process-file "true")))
             (should-not (zerop (process-file "false")))
             (should-not (zerop (process-file "binary-does-not-exist")))
@@ -7665,7 +7661,6 @@ This requires restrictions of file name syntax."
 (ert-deftest tramp-test41-special-characters ()
   "Check special characters in file names."
   (skip-unless (tramp--test-enabled))
-  (skip-unless (not (getenv "EMACS_HYDRA_CI"))) ; SLOW ~ 245s
   (skip-unless (not (tramp--test-rsync-p)))
   (skip-unless (not (tramp--test-rclone-p)))
   (skip-unless (not (or (eq system-type 'darwin) (tramp--test-macos-p))))
@@ -7744,7 +7739,6 @@ This requires restrictions of file name syntax."
 (ert-deftest tramp-test42-utf8 ()
   "Check UTF8 encoding in file names and file contents."
   (skip-unless (tramp--test-enabled))
-  (skip-unless (not (getenv "EMACS_HYDRA_CI"))) ; SLOW ~ 620s
   (skip-unless (not (tramp--test-container-p)))
   (skip-unless (not (tramp--test-rsync-p)))
   (skip-unless (not (tramp--test-scp-p)))
@@ -7902,17 +7896,12 @@ process sentinels.  They shall not disturb each other."
             (cond
              ((ignore-errors
                (string-to-number (getenv "REMOTE_PARALLEL_PROCESSES"))))
-             ((getenv "EMACS_HYDRA_CI") 5)
              (t 10)))
            ;; PuTTY-based methods can only share up to 10 connections.
            (tramp-use-connection-share
             (if (and (tramp--test-putty-p) (>= number-proc 10))
                 'suppress (bound-and-true-p tramp-use-connection-share)))
-           ;; On hydra, timings are bad.
-           (timer-repeat
-            (cond
-             ((getenv "EMACS_HYDRA_CI") 10)
-             (t 1)))
+           (timer-repeat 1)
            ;; This is when all timers start.  We check inside the
            ;; timer function, that we don't exceed timeout.
            (timer-start (current-time))
@@ -8102,6 +8091,58 @@ process sentinels.  They shall not disturb each other."
     (delete-directory tmp-name)
     (delete-file (concat tmp-name ".tar.gz"))))
 
+;; More exhaustive tests are performed in filenotify-tests.el,
+;; selector "remote".
+(ert-deftest tramp-test46-file-notifications ()
+  "Check that Tramp handles file notifications."
+  (skip-unless (tramp--test-enabled))
+
+  (let* ((tmp-name (tramp--test-make-temp-name))
+         ;(file-notify-debug t)
+         (desc1
+          (ignore-error file-notify-error
+            (file-notify-add-watch
+             tmp-name '(change attribute-change) #'ignore)))
+         (desc2
+          (ignore-error file-notify-error
+            (file-notify-add-watch
+             ert-remote-temporary-file-directory
+             '(change attribute-change) #'ignore))))
+    (skip-unless (and desc1 desc2))
+
+    (unwind-protect
+        (progn
+          (tramp--test-message "%S" desc1)
+          (should-not (file-exists-p tmp-name))
+          (should (file-notify-valid-p desc1))
+          (should (file-notify-valid-p desc2))
+
+          ;; Create the file.
+          (write-region "foo" nil tmp-name)
+          (should (file-exists-p tmp-name))
+          ;; Modify.
+          (write-region "foo" nil tmp-name)
+          (should (file-exists-p tmp-name))
+          ;; Delete.
+          (delete-file tmp-name)
+          (should-not (file-exists-p tmp-name))
+
+          (while (read-event nil nil 0.1))
+          ;; This has been stopped because the file was deleted.
+          (should-not (file-notify-valid-p desc1))
+
+          ;; This is still valid.
+          (should (file-notify-valid-p desc2))
+          (file-notify-rm-watch desc2)
+          (should-not (file-notify-valid-p desc2)))
+
+      ;; Cleanup.
+      (ignore-errors (delete-file tmp-name))
+      ;; `file-notify-rm-all-watches' exists since Emacs 30.1.
+      ;; We don't want to see compiler warnings for older Emacsen.
+      (when (fboundp 'file-notify-rm-all-watches)
+        (with-no-warnings (file-notify-rm-all-watches))))))
+
 (ert-deftest tramp-test47-read-password ()
   "Check Tramp password handling."
   :tags '(:expensive-test)
@@ -8656,6 +8697,9 @@ If INTERACTIVE is non-nil, the tests are run interactively."
 ;; * Check, why direct async processes do not work for
 ;;   `tramp-test45-asynchronous-requests'.
 
+;; Starting with Emacs 29, use `ert-with-temp-file' and
+;; `ert-with-temp-directory'.
+
 (provide 'tramp-tests)
 
 ;;; tramp-tests.el ends here