Adapt shadowfile.el for Tramp (Bug#4526, Bug#4846)

* etc/NEWS: Mention changes in shadowfile.el.

* lisp/shadowfile.el (top): Require 'tramp instead of 'ange-ftp.
(shadow-cluster): New defstruct.
(shadow-make-cluster, shadow-cluster-name, shadow-cluster-primary)
(shadow-cluster-regexp, shadow-get-user)
(shadow-parse-fullname): Remove.
(shadow-info-file, shadow-todo-file, shadow-system-name)
(shadow-homedir, shadow-regexp-superquote, shadow-suffix)
(shadow-set-cluster, shadow-get-cluster, shadow-site-name)
(shadow-name-site, shadow-site-primary, shadow-site-cluster)
(shadow-read-site, shadow-parse-name, shadow-make-fullname)
(shadow-replace-name-component, shadow-local-file)
(shadow-expand-cluster-in-file-name, shadow-contract-file-name)
(shadow-same-site, shadow-file-match, shadow-define-cluster)
(shadow-define-literal-group, shadow-define-regexp-group)
(shadow-make-group, shadow-shadows-of-1, shadow-read-files)
(shadow-write-info-file, shadow-write-todo-file)
(shadow-initialize): Adapt variables and functions.

* test/lisp/shadowfile-tests.el: New file.

3 files changed, 1114 insertions, 232 deletions

diff --git a/etc/NEWS b/etc/NEWS
index 92331108e95..1551c36c5a3 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -94,12 +94,20 @@ it now shows the global revision number, in the form of its changeset
 hash value.  To get back the previous behavior, customize the new
 option 'vc-hg-symbolic-revision-styles' to the value '("{rev}")'.
 
+---
+** shadowfile.el has been rewritten to support Tramp file names.
+
 
 * New Modes and Packages in Emacs 26.2
 
 
 * Incompatible Lisp Changes in Emacs 26.2
 
+---
+** shadowfile config files have changed their syntax.
+Existing files "~/.emacs.d/shadows" and "~/.emacs.d/shadow_todo" must
+be removed prior using the changed 'shadow-*' commands.
+
 
 * Lisp Changes in Emacs 26.2
 
diff --git a/lisp/shadowfile.el b/lisp/shadowfile.el
index 0095d6959ef..e1a9b8e1d98 100644
--- a/lisp/shadowfile.el
+++ b/lisp/shadowfile.el
@@ -25,37 +25,38 @@
 ;;  This package helps you to keep identical copies of files in more than one
 ;;  place - possibly on different machines.  When you save a file, it checks
 ;;  whether it is on the list of files with "shadows", and if so, it tries to
-;;  copy it when you exit Emacs (or use the shadow-copy-files command).
+;;  copy it when you exit Emacs (or use the `shadow-copy-files' command).
 
 ;; Installation & Use:
 
-;;  Add clusters (if necessary) and file groups with shadow-define-cluster,
-;;  shadow-define-literal-group, and shadow-define-regexp-group (see the
+;;  Add clusters (if necessary) and file groups with `shadow-define-cluster',
+;;  `shadow-define-literal-group', and `shadow-define-regexp-group' (see the
 ;;  documentation for these functions for information on how and when to use
 ;;  them).  After doing this once, everything should be automatic.
 
-;;  The lists of clusters and shadows are saved in a ~/.emacs.d/shadows
-;;  (`shadow-info-file') file, so that they can be remembered from one
-;;  Emacs session to another, even (as much as possible) if the Emacs
-;;  session terminates abnormally.  The files needing to be copied are
-;;  stored in `shadow-todo-file'; if a file cannot be copied for any
-;;  reason, it will stay on the list to be tried again next time.  The
-;;  `shadow-info-file' file should itself have shadows on all your accounts
-;;  so that the information in it is consistent everywhere, but
-;;  `shadow-todo-file' is local information and should have no shadows.
+;;  The lists of clusters and shadows are saved in `shadow-info-file',
+;;  so that they can be remembered from one Emacs session to another,
+;;  even (as much as possible) if the Emacs session terminates
+;;  abnormally.  The files needing to be copied are stored in
+;;  `shadow-todo-file'; if a file cannot be copied for any reason, it
+;;  will stay on the list to be tried again next time.  The
+;;  `shadow-info-file' file should itself have shadows on all your
+;;  accounts so that the information in it is consistent everywhere,
+;;  but `shadow-todo-file' is local information and should have no
+;;  shadows.
 
 ;;  If you do not want to copy a particular file, you can answer "no" and
-;;  be asked again next time you hit C-x 4 s or exit Emacs.  If you do not
-;;  want to be asked again, use shadow-cancel, and you will not be asked
+;;  be asked again next time you hit "C-x 4 s" or exit Emacs.  If you do not
+;;  want to be asked again, use "M-x shadow-cancel", and you will not be asked
 ;;  until you change the file and save it again.  If you do not want to
 ;;  shadow that file ever again, you can edit it out of the shadows
-;;  buffer.  Anytime you edit the shadows buffer, you must type M-x
-;;  shadow-read-files to load in the new information, or your changes will
+;;  buffer.  Anytime you edit the shadows buffer, you must type "M-x
+;;  shadow-read-files" to load in the new information, or your changes will
 ;;  be overwritten!
 
 ;; Bugs & Warnings:
 ;;
-;;  - It is bad to have two emacses both running shadowfile at the same
+;;  - It is bad to have two Emacsen both running shadowfile at the same
 ;;  time.  It tries to detect this condition, but is not always successful.
 ;;
 ;;  - You have to be careful not to edit a file in two locations
@@ -64,19 +65,16 @@
 ;;
 ;;  - It ought to check modification times of both files to make sure
 ;;  it is doing the right thing.  This will have to wait until
-;;  file-newer-than-file-p works between machines.
+;;  `file-newer-than-file-p' works between machines.
 ;;
 ;;  - It will not make directories for you, it just fails to copy files
 ;;  that belong in non-existent directories.
-;;
-;;  Please report any bugs to me (boris@gnu.org).  Also let me know
-;;  if you have suggestions or would like to be informed of updates.
 
 
 ;;; Code:
 
 (require 'cl-lib)
-(require 'ange-ftp)
+(require 'tramp)
 
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ;;; Variables
@@ -107,35 +105,35 @@ files that have been changed and need to be copied to other systems."
   :type 'boolean
   :group 'shadow)
 
-;; FIXME in a sense, this changed in 24.4 (addition of locate-user-emacs-file),
-;; but due to the weird way this variable is initialized to nil, it didn't
-;; literally change.  Same for shadow-todo-file.
-(defcustom shadow-info-file nil
+(defcustom shadow-info-file (locate-user-emacs-file "shadows" ".shadows")
   "File to keep shadow information in.
 The `shadow-info-file' should be shadowed to all your accounts to
 ensure consistency.  Default: ~/.emacs.d/shadows"
-  :type '(choice (const nil) file)
-  :group 'shadow)
+  :type 'file
+  :group 'shadow
+  :version "26.2")
 
-(defcustom shadow-todo-file nil
+(defcustom shadow-todo-file
+  (locate-user-emacs-file "shadow_todo" ".shadow_todo")
   "File to store the list of uncopied shadows in.
 This means that if a remote system is down, or for any reason you cannot or
 decide not to copy your shadow files at the end of one Emacs session, it will
 remember and ask you again in your next Emacs session.
 This file must NOT be shadowed to any other system, it is host-specific.
 Default: ~/.emacs.d/shadow_todo"
-  :type '(choice (const nil) file)
-  :group 'shadow)
+  :type 'file
+  :group 'shadow
+  :version "26.2")
 
 
 ;;; The following two variables should in most cases initialize themselves
 ;;; correctly.  They are provided as variables in case the defaults are wrong
 ;;; on your machine (and for efficiency).
 
-(defvar shadow-system-name (system-name)
-  "The complete hostname of this machine.")
+(defvar shadow-system-name (concat "/" (system-name) ":")
+  "The identification for local files on this machine.")
 
-(defvar shadow-homedir nil
+(defvar shadow-homedir "~"
   "Your home directory on this machine.")
 
 ;;;
@@ -186,12 +184,12 @@ created by `shadow-define-regexp-group'.")
   (car list))
 
 (defun shadow-regexp-superquote (string)
-  "Like `regexp-quote', but includes the ^ and $.
+  "Like `regexp-quote', but includes the \\` and \\'.
 This makes sure regexp matches nothing but STRING."
-  (concat "^" (regexp-quote string) "$"))
+  (concat "\\`" (regexp-quote string) "\\'"))
 
 (defun shadow-suffix (prefix string)
-  "If PREFIX begins STRING, return the rest.
+  "If PREFIX begins with STRING, return the rest.
 Return value is non-nil if PREFIX and STRING are `string=' up to the length of
 PREFIX."
   (let ((lp (length prefix))
@@ -204,70 +202,66 @@ PREFIX."
 ;;; Clusters and sites
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 
-;;; I use the term `site' to refer to a string which may be the name of a
-;;; cluster or a literal hostname.  All user-level commands should accept
-;;; either.
-
-(defun shadow-make-cluster (name primary regexp)
-  "Create a shadow cluster.
-It is called NAME, uses the PRIMARY hostname and REGEXP matching all
-hosts in the cluster.  The variable `shadow-clusters' associates the
-names of clusters to these structures.  This function is for program
-use: to create clusters interactively, use `shadow-define-cluster'
-instead."
-  (list name primary regexp))
-
-(defmacro shadow-cluster-name (cluster)
-  "Return the name of the CLUSTER."
-  (list 'elt cluster 0))
+;;; I use the term `site' to refer to a string which may be the
+;;; cluster identification "/name:", a remote identification
+;;; "/method:user@host:", or "/system-name:' (the value of
+;;; `shadow-system-name') for the location of local files.  All
+;;; user-level commands should accept either.
 
-(defmacro shadow-cluster-primary (cluster)
-  "Return the primary hostname of a CLUSTER."
-  (list 'elt cluster 1))
-
-(defmacro shadow-cluster-regexp (cluster)
-  "Return the regexp matching hosts in a CLUSTER."
-  (list 'elt cluster 2))
+(cl-defstruct (shadow-cluster (:type list) :named) name primary regexp)
 
 (defun shadow-set-cluster (name primary regexp)
   "Put cluster NAME on the list of clusters.
 Replace old definition, if any.  PRIMARY and REGEXP are the
 information defining the cluster.  For interactive use, call
 `shadow-define-cluster' instead."
-  (let ((rest (cl-remove-if (lambda (x) (equal name (car x)))
+  (let ((rest (cl-remove-if (lambda (x) (equal name (shadow-cluster-name x)))
                             shadow-clusters)))
     (setq shadow-clusters
-          (cons (shadow-make-cluster name primary regexp)
+          (cons (make-shadow-cluster :name name :primary primary :regexp regexp)
                 rest))))
 
-(defmacro shadow-get-cluster (name)
+(defun shadow-get-cluster (name)
   "Return cluster named NAME, or nil."
-  (list 'assoc name 'shadow-clusters))
+  (shadow-find
+   (lambda (x) (string-equal (shadow-cluster-name x) name))
+   shadow-clusters))
+
+;;; SITES
+
+(defun shadow-site-name (site)
+  "Return name if SITE has the form \"/name:\", otherwise SITE."
+  (if (string-match "\\`/\\(\\w+\\):\\'" site)
+      (match-string 1 site) site))
+
+(defun shadow-name-site (name)
+  "Return \"/name:\" if NAME has word syntax, otherwise NAME."
+  (if (string-match "\\`\\w+\\'" name)
+      (format "/%s:"name) name))
 
 (defun shadow-site-primary (site)
-  "If SITE is a cluster, return primary host, otherwise return SITE."
-  (let ((c (shadow-get-cluster site)))
-    (if c
-        (shadow-cluster-primary c)
+  "If SITE is a cluster, return primary identification, otherwise return SITE."
+  (let ((cluster (shadow-get-cluster (shadow-site-name site))))
+    (if cluster
+        (shadow-cluster-primary cluster)
       site)))
 
-;;; SITES
-
 (defun shadow-site-cluster (site)
-  "Given a SITE (hostname or cluster name), return cluster it is in, or nil."
-  (or (assoc site shadow-clusters)
+  "Given a SITE, return cluster it is in, or nil."
+  (or (shadow-get-cluster (shadow-site-name site))
       (shadow-find
-       (function (lambda (x)
-                   (string-match (shadow-cluster-regexp x)
-                                 site)))
+       (lambda (x)
+         (string-match (shadow-cluster-regexp x) (shadow-name-site site)))
        shadow-clusters)))
 
 (defun shadow-read-site ()
-  "Read a cluster name or hostname from the minibuffer."
-  (let ((ans (completing-read "Host or cluster name [RET when done]: "
+  "Read a cluster name or host identification from the minibuffer."
+  (let ((ans (completing-read "Host identification or cluster name: "
                               shadow-clusters)))
-    (if (equal "" ans)
-        nil
+    (when (or (shadow-get-cluster (shadow-site-name ans))
+              (string-equal ans shadow-system-name)
+              (string-equal ans (shadow-site-name shadow-system-name))
+              (setq ans (file-remote-p ans)))
       ans)))
 
 (defun shadow-site-match (site1 site2)
@@ -281,63 +275,95 @@ be matched against the primary of SITE2."
             (string-match (shadow-cluster-regexp cluster1) primary2)
           (string-equal site1 primary2)))))
 
-(defun shadow-get-user (site)
-  "Return the default username for a SITE."
-  (ange-ftp-get-user (shadow-site-primary site)))
-
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ;;; Filename manipulation
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 
-(defun shadow-parse-fullname (fullname)
-  "Parse FULLNAME into (site user path) list.
-Leave it alone if it already is one.  Return nil if the argument is
-not a full ange-ftp pathname."
-  (if (listp fullname)
-      fullname
-    (ange-ftp-ftp-name fullname)))
-
 (defun shadow-parse-name (name)
-  "Parse any NAME into (site user name) list.
-Argument can be a simple name, full ange-ftp name, or already a hup list."
-  (or (shadow-parse-fullname name)
-      (list shadow-system-name
-            (user-login-name)
-            name)))
-
-(defsubst shadow-make-fullname (host user name)
-  "Make an ange-ftp style fullname out of HOST, USER (optional), and NAME.
-This is probably not as general as it ought to be."
-  (concat "/"
-          (if user (concat user "@"))
-          host ":"
-          name))
+  "Parse any NAME into a `tramp-file-name' structure.
+Argument can be a simple name, remote file name, or already a
+`tramp-file-name' structure."
+  (cond
+   ((null name) nil)
+   ((tramp-file-name-p name) name)
+   ((file-remote-p name) (tramp-dissect-file-name name))
+   ((shadow-local-file name)
+    (make-tramp-file-name
+     :host (shadow-site-name shadow-system-name)
+     :localname (shadow-local-file name)))
+   ;; Cluster name.
+   ((string-match "^/\\([^:/]+\\):\\([^:]*\\)$" name)
+    (let ((name (match-string 1 name))
+          (file (match-string 2 name)))
+      (when (shadow-get-cluster name)
+        (make-tramp-file-name :host name :localname file))))))
+
+(defsubst shadow-make-fullname (hup &optional host name)
+  "Make a Tramp style fullname out of HUP, a `tramp-file-name' structure.
+Replace HOST, and NAME when non-nil."
+  (let ((hup (copy-tramp-file-name hup)))
+    (when host (setf (tramp-file-name-host hup) host))
+    (when name (setf (tramp-file-name-localname hup) name))
+    (if (null (tramp-file-name-method hup))
+        (format
+         "/%s:%s" (tramp-file-name-host hup) (tramp-file-name-localname hup))
+      (tramp-make-tramp-file-name
+       (tramp-file-name-method hup)
+       (tramp-file-name-user hup)
+       (tramp-file-name-domain hup)
+       (tramp-file-name-host hup)
+       (tramp-file-name-port hup)
+       (tramp-file-name-localname hup)
+       (tramp-file-name-hop hup)))))
 
 (defun shadow-replace-name-component (fullname newname)
   "Return FULLNAME with the name component changed to NEWNAME."
-  (let ((hup (shadow-parse-fullname fullname)))
-    (shadow-make-fullname (nth 0 hup) (nth 1 hup) newname)))
+  (concat (file-remote-p fullname) newname))
 
 (defun shadow-local-file (file)
-  "If FILE is at this site, remove /user@host part.
-If refers to a different system or a different user on this system,
-return nil."
-  (let ((hup (shadow-parse-fullname file)))
-    (cond ((null hup) file)
-          ((and (shadow-site-match (nth 0 hup) shadow-system-name)
-                (string-equal (nth 1 hup) (user-login-name)))
-           (nth 2 hup))
-          (t nil))))
+  "If FILE is not remote, return it.
+If it refers to a different system, return nil."
+  (cond
+   ((null file) nil)
+   ;; `tramp-file-name' structure.
+   ((and (tramp-file-name-p file) (null (tramp-file-name-method file)))
+    (tramp-file-name-localname file))
+   ((tramp-file-name-p file) nil)
+   ;; Local host name.
+   ((string-match
+     (format "^%s\\([^:]*\\)$" (regexp-quote shadow-system-name)) file)
+    (match-string 1 file))
+   ;; Cluster name.
+   ((and (string-match "^/\\([^:/]+\\):\\([^:]*\\)$" file)
+         (shadow-get-cluster (match-string 1 file)))
+    (let ((file (match-string 2 file))
+          (primary
+           (shadow-cluster-primary
+            (shadow-get-cluster (match-string 1 file)))))
+      (when (string-equal primary shadow-system-name) (setq primary nil))
+      (shadow-local-file (concat primary file))))
+   ;; Local name.
+   ((null (file-remote-p file)) file)))
 
 (defun shadow-expand-cluster-in-file-name (file)
   "If hostname part of FILE is a cluster, expand it to cluster's primary hostname.
 Will return the name bare if it is a local file."
-  (let ((hup (shadow-parse-name file)))
-    (cond ((null hup) file)
-          ((shadow-local-file hup))
-          ((shadow-make-fullname (shadow-site-primary (nth 0 hup))
-                                 (nth 1 hup)
-                                 (nth 2 hup))))))
+  (when (stringp file)
+    (cond
+     ;; Local file.
+     ((shadow-local-file file))
+     ;; Cluster name.
+     ((string-match "^\\(/[^:/]+:\\)[^:]*$" file)
+      (let ((primary
+             (save-match-data
+               (shadow-cluster-primary
+                (shadow-get-cluster
+                 (shadow-site-name (match-string 1 file)))))))
+        (if (not primary)
+            file
+          (setq file (replace-match primary nil nil file 1))
+          (or (shadow-local-file file) file))))
+     (t file))))
 
 (defun shadow-expand-file-name (file &optional default)
   "Expand file name and get FILE's true name."
@@ -352,46 +378,50 @@ true."
          (homedir (if (shadow-local-file hup)
                       shadow-homedir
                     (file-name-as-directory
-                     (nth 2 (shadow-parse-fullname
-                             (expand-file-name
-                              (shadow-make-fullname
-                               (nth 0 hup) (nth 1 hup) "~")))))))
-         (suffix (shadow-suffix homedir (nth 2 hup)))
-         (cluster (shadow-site-cluster (nth 0 hup))))
+                     (file-local-name
+                      (expand-file-name (shadow-make-fullname hup nil "~"))))))
+         (suffix (shadow-suffix homedir (tramp-file-name-localname hup)))
+         (cluster (shadow-site-cluster (shadow-make-fullname hup nil ""))))
+    (when cluster
+      (setf (tramp-file-name-method hup) nil
+            (tramp-file-name-host hup) (shadow-cluster-name cluster)))
     (shadow-make-fullname
-     (if cluster
-         (shadow-cluster-name cluster)
-       (nth 0 hup))
-     (nth 1 hup)
+     hup nil
      (if suffix
-         (concat "~/" suffix)
-       (nth 2 hup)))))
+         (concat "~/" suffix)
+       (tramp-file-name-localname hup)))))
 
 (defun shadow-same-site (pattern file)
   "True if the site of PATTERN and of FILE are on the same site.
-If usernames are supplied, they must also match exactly.  PATTERN and FILE may
-be lists of host, user, name, or ange-ftp file names.  FILE may also be just a
-local filename."
-  (let ((pattern-sup (shadow-parse-fullname pattern))
+PATTERN and FILE may be Tramp vectors, or remote file names.
+FILE may also be just a local filename."
+  (let ((pattern-sup (shadow-parse-name pattern))
         (file-sup    (shadow-parse-name file)))
     (and
-     (shadow-site-match (nth 0 pattern-sup) (nth 0 file-sup))
-     (or (null (nth 1 pattern-sup))
-         (string-equal (nth 1 pattern-sup) (nth 1 file-sup))))))
+     (shadow-site-match
+      (tramp-file-name-host pattern-sup) (tramp-file-name-host file-sup))
+     (or (null (tramp-file-name-user pattern-sup))
+         (string-equal
+          (tramp-file-name-user pattern-sup)
+          (tramp-file-name-user file-sup))))))
 
 (defun shadow-file-match (pattern file &optional regexp)
  "Return t if PATTERN matches FILE.
 If REGEXP is supplied and non-nil, the file part of the pattern is a regular
-expression, otherwise it must match exactly.  The sites and usernames must
-match---see `shadow-same-site'.  The pattern must be in full ange-ftp format,
+expression, otherwise it must match exactly.  The sites must
+match---see `shadow-same-site'.  The pattern must be in full Tramp format,
 but the file can be any valid filename.  This function does not do any
 filename expansion or contraction, you must do that yourself first."
- (let* ((pattern-sup (shadow-parse-fullname pattern))
+ (let* ((pattern-sup (shadow-parse-name pattern))
         (file-sup (shadow-parse-name file)))
    (and (shadow-same-site pattern-sup file-sup)
         (if regexp
-            (string-match (nth 2 pattern-sup) (nth 2 file-sup))
-          (string-equal (nth 2 pattern-sup) (nth 2 file-sup))))))
+            (string-match
+             (tramp-file-name-localname pattern-sup)
+             (tramp-file-name-localname file-sup))
+          (string-equal
+           (tramp-file-name-localname pattern-sup)
+           (tramp-file-name-localname file-sup))))))
 
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ;;; User-level Commands
@@ -405,30 +435,34 @@ one of them is sufficient to update the file on all of them.  Clusters are
 defined by a name, the network address of a primary host (the one we copy
 files to), and a regular expression that matches the hostnames of all the
 sites in the cluster."
-  (interactive (list (completing-read "Cluster name: " shadow-clusters () ())))
+  (interactive (list (completing-read "Cluster name: " shadow-clusters)))
   (let* ((old (shadow-get-cluster name))
-         (primary (read-string "Primary host: "
-                               (if old (shadow-cluster-primary old)
-                                 name)))
-         (regexp   (let (try-regexp)
-                     (while (not
-                             (string-match
-                              (setq try-regexp
+         (primary (let (try-primary)
+                    (while (not
+                            (or
+                             (string-equal
+                              (setq try-primary
                                     (read-string
-                                     "Regexp matching all host names: "
-                                     (if old (shadow-cluster-regexp old)
-                                       (shadow-regexp-superquote primary))))
-                              primary))
-                       (message "Regexp doesn't include the primary host!")
-                       (sit-for 2))
-                     try-regexp))
-;        (username (read-no-blanks-input
-;                   (format "Username (default %s): "
-;                           (shadow-get-user primary))
-;                   (if old (or (shadow-cluster-username old) "")
-;                     (user-login-name))))
-         )
-;    (if (string-equal "" username) (setq username nil))
+                                     "Primary host: "
+                                     (if old (shadow-cluster-primary old)
+                                       name)))
+                              shadow-system-name)
+                             (file-remote-p try-primary)))
+                      (message "Not a valid primary!")
+                      (sit-for 2))
+                    try-primary))
+         (regexp  (let (try-regexp)
+                    (while (not
+                            (string-match
+                             (setq try-regexp
+                                   (read-string
+                                    "Regexp matching all host names: "
+                                    (if old (shadow-cluster-regexp old)
+                                      (shadow-regexp-superquote primary))))
+                             primary))
+                      (message "Regexp doesn't include the primary host!")
+                      (sit-for 2))
+                    try-regexp)))
     (shadow-set-cluster name primary regexp)))
 
 ;;;###autoload
@@ -438,20 +472,14 @@ It may have different filenames on each site.  When this file is edited, the
 new version will be copied to each of the other locations.  Sites can be
 specific hostnames, or names of clusters (see `shadow-define-cluster')."
   (interactive)
-  (let* ((hup (shadow-parse-fullname
+  (let* ((hup (shadow-parse-name
                (shadow-contract-file-name (buffer-file-name))))
-         (name (nth 2 hup))
-         user site group)
+         (name (tramp-file-name-localname hup))
+         site group)
     (while (setq site (shadow-read-site))
-      (setq user (read-string (format "Username (default %s): "
-                                      (shadow-get-user site)))
-            name (read-string "Filename: " name))
-      (setq group (cons (shadow-make-fullname site
-                                              (if (string-equal "" user)
-                                                  (shadow-get-user site)
-                                                user)
-                                              name)
-                        group)))
+      (setq name (read-string "Filename: " name)
+            hup (shadow-parse-name (shadow-contract-file-name name))
+            group (cons (shadow-make-fullname hup site) group)))
     (setq shadow-literal-groups (cons group shadow-literal-groups)))
   (shadow-write-info-file))
 
@@ -468,19 +496,12 @@ function).  Each site can be either a hostname or the name of a cluster (see
                  "Filename regexp: "
                  (if (buffer-file-name)
                      (shadow-regexp-superquote
-                      (nth 2
-                           (shadow-parse-name
-                            (shadow-contract-file-name
-                             (buffer-file-name))))))))
-        site sites usernames)
+                      (file-local-name (buffer-file-name))))))
+        site sites)
     (while (setq site (shadow-read-site))
-      (setq sites (cons site sites))
-      (setq usernames
-            (cons (read-string (format "Username for %s: " site)
-                               (shadow-get-user site))
-                  usernames)))
+      (setq sites (cons site sites)))
     (setq shadow-regexp-groups
-          (cons (shadow-make-group regexp sites usernames)
+          (cons (shadow-make-group regexp sites)
                 shadow-regexp-groups))
     (shadow-write-info-file)))
 
@@ -537,14 +558,14 @@ permanently, remove the group from `shadow-literal-groups' or
 ;;; Internal functions
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 
-(defun shadow-make-group (regexp sites usernames)
+(defun shadow-make-group (regexp sites)
   "Make a description of a file group---
-actually a list of regexp ange-ftp file names---from REGEXP (name of file to
-be shadowed), list of SITES, and corresponding list of USERNAMES for each
-site."
+actually a list of regexp Tramp file names---from REGEXP (name of file to
+be shadowed), and list of SITES"
   (if sites
-      (cons (shadow-make-fullname (car sites) (car usernames) regexp)
-            (shadow-make-group regexp (cdr sites) (cdr usernames)))
+      (cons (shadow-make-fullname
+             (shadow-parse-name (shadow-site-primary (car sites))) nil regexp)
+            (shadow-make-group regexp (cdr sites)))
     nil))
 
 (defun shadow-copy-file (s)
@@ -601,7 +622,9 @@ Consider them as regular expressions if third arg REGEXP is true."
                            (car groups))))
         (append (cond ((equal nonmatching (car groups)) nil)
                       (regexp
-                       (let ((realname (nth 2 (shadow-parse-fullname file))))
+                       (let ((realname
+                              (tramp-file-name-localname
+                               (shadow-parse-name file))))
                          (mapcar
                           (function
                            (lambda (x)
@@ -636,9 +659,8 @@ PAIR must be `eq' to one of the elements of that list."
 Thus restores shadowfile's state from your last Emacs session.
 Return t unless files were locked; then return nil."
   (interactive)
-  (if (and (fboundp 'file-locked-p)
-           (or (stringp (file-locked-p shadow-info-file))
-               (stringp (file-locked-p shadow-todo-file))))
+  (if (or (stringp (file-locked-p shadow-info-file))
+          (stringp (file-locked-p shadow-todo-file)))
       (progn
         (message "Shadowfile is running in another Emacs; can't have two.")
         (beep)
@@ -647,7 +669,7 @@ Return t unless files were locked; then return nil."
     (save-current-buffer
       (when shadow-info-file
         (set-buffer (setq shadow-info-buffer
-                          (find-file-noselect shadow-info-file)))
+                          (find-file-noselect shadow-info-file 'nowarn)))
         (when (and (not (buffer-modified-p))
                    (file-newer-than-file-p (make-auto-save-file-name)
                                            shadow-info-file))
@@ -680,6 +702,7 @@ defined, the old hashtable info is invalid."
         (if (not shadow-info-buffer)
             (setq shadow-info-buffer (find-file-noselect shadow-info-file)))
         (set-buffer shadow-info-buffer)
+        (setq buffer-read-only nil)
         (delete-region (point-min) (point-max))
         (shadow-insert-var 'shadow-clusters)
         (shadow-insert-var 'shadow-literal-groups)
@@ -692,6 +715,7 @@ With non-nil argument also saves the buffer."
     (if (not shadow-todo-buffer)
         (setq shadow-todo-buffer (find-file-noselect shadow-todo-file)))
     (set-buffer shadow-todo-buffer)
+    (setq buffer-read-only nil)
     (delete-region (point-min) (point-max))
     (shadow-insert-var 'shadow-files-to-copy)
     (if save (shadow-save-todo-file))))
@@ -765,24 +789,6 @@ look for files that have been changed and need to be copied to other systems."
        (kill-emacs)))
 
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
-;;; Lucid Emacs compatibility
-;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
-
-;; This is on hold until someone tells me about a working version of
-;; map-ynp for Lucid Emacs.
-
-;(when (string-match "Lucid" emacs-version)
-;  (require 'symlink-fix)
-;  (require 'ange-ftp)
-;  (require 'map-ynp)
-;  (if (not (fboundp 'file-truename))
-;      (fset 'shadow-expand-file-name
-;           (symbol-function 'symlink-expand-file-name)))
-;  (if (not (fboundp 'ange-ftp-ftp-name))
-;      (fset 'ange-ftp-ftp-name
-;           (symbol-function 'ange-ftp-ftp-name))))
-
-;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ;;; Hook us up
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 
@@ -790,18 +796,10 @@ look for files that have been changed and need to be copied to other systems."
 (defun shadow-initialize ()
   "Set up file shadowing."
   (interactive)
-  (if (null shadow-homedir)
-      (setq shadow-homedir
-            (file-name-as-directory (shadow-expand-file-name "~"))))
-  (if (null shadow-info-file)
-      (setq shadow-info-file
-            ;; FIXME: Move defaults to their defcustom.
-            (shadow-expand-file-name
-             (locate-user-emacs-file "shadows" ".shadows"))))
-  (if (null shadow-todo-file)
-      (setq shadow-todo-file
-            (shadow-expand-file-name
-             (locate-user-emacs-file "shadow_todo" ".shadow_todo"))))
+  (setq shadow-homedir
+        (file-name-as-directory (shadow-expand-file-name shadow-homedir))
+        shadow-info-file (shadow-expand-file-name shadow-info-file)
+        shadow-todo-file (shadow-expand-file-name shadow-todo-file))
   (if (not (shadow-read-files))
       (progn
         (message "Shadowfile information files not found - aborting")
diff --git a/test/lisp/shadowfile-tests.el b/test/lisp/shadowfile-tests.el
new file mode 100644
index 00000000000..5ded94480ec
--- /dev/null
+++ b/test/lisp/shadowfile-tests.el
@@ -0,0 +1,876 @@
+;;; shadowfile-tests.el --- Tests of shadowfile
+
+;; Copyright (C) 2018 Free Software Foundation, Inc.
+
+;; Author: Michael Albinus <michael.albinus@gmx.de>
+
+;; This program is free software: you can redistribute it and/or
+;; modify it under the terms of the GNU General Public License as
+;; published by the Free Software Foundation, either version 3 of the
+;; License, or (at your option) any later version.
+;;
+;; This program is distributed in the hope that it will be useful, but
+;; WITHOUT ANY WARRANTY; without even the implied warranty of
+;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+;; General Public License for more details.
+;;
+;; You should have received a copy of the GNU General Public License
+;; along with this program.  If not, see `http://www.gnu.org/licenses/'.
+
+;;; Commentary:
+
+;; A whole test run can be performed calling the command `shadowfile-test-all'.
+
+;;; Code:
+
+(require 'ert)
+(require 'shadowfile)
+(require 'tramp)
+
+;; There is no default value on w32 systems, which could work out of the box.
+(defconst shadow-test-remote-temporary-file-directory
+  (cond
+   ((getenv "REMOTE_TEMPORARY_FILE_DIRECTORY"))
+   ((eq system-type 'windows-nt) null-device)
+   (t (add-to-list
+       'tramp-methods
+       '("mock"
+         (tramp-login-program        "sh")
+         (tramp-login-args           (("-i")))
+         (tramp-remote-shell         "/bin/sh")
+         (tramp-remote-shell-args    ("-c"))
+         (tramp-connection-timeout   10)))
+      (add-to-list
+       'tramp-default-host-alist
+       `("\\`mock\\'" nil ,(system-name)))
+      ;; Emacs' Makefile sets $HOME to a nonexistent value.  Needed in
+      ;; batch mode only, therefore.  It cannot be
+      ;; `temporary-directory', because the tests with "~" would fail.
+      (unless (and (null noninteractive) (file-directory-p "~/"))
+        (setenv "HOME" invocation-directory))
+      (format "/mock::%s" temporary-file-directory)))
+  "Temporary directory for Tramp tests.")
+
+(defconst shadow-test-info-file
+  (expand-file-name "shadows_test" temporary-file-directory)
+  "File to keep shadow information in during tests.")
+
+(defconst shadow-test-todo-file
+  (expand-file-name "shadow_todo_test" temporary-file-directory)
+  "File to store the list of uncopied shadows in during tests.")
+
+(ert-deftest shadow-test00-clusters ()
+  "Check cluster definitions.
+Per definition, all files are identical on the different hosts of
+a cluster (or site).  This is not tested here; it must be
+guaranteed by the originator of a cluster definition."
+  (skip-unless (file-remote-p shadow-test-remote-temporary-file-directory))
+
+  (let ((text-quoting-style 'grave) ;; We inspect the *Messages* buffer!
+        (inhibit-message t)
+        (shadow-info-file shadow-test-info-file)
+        (shadow-todo-file shadow-test-todo-file)
+        shadow-clusters
+        cluster primary regexp mocked-input)
+    (unwind-protect
+        ;; We must mock `read-from-minibuffer' and `read-string', in
+        ;; order to avoid interactive arguments.
+        (cl-letf* (((symbol-function 'read-from-minibuffer)
+                    (lambda (&rest args) (pop mocked-input)))
+                   ((symbol-function 'read-string)
+                    (lambda (&rest args) (pop mocked-input))))
+
+          ;; Cleanup.
+          (when (file-exists-p shadow-info-file)
+            (delete-file shadow-info-file))
+          (when (file-exists-p shadow-todo-file)
+            (delete-file shadow-todo-file))
+
+          ;; Define a cluster.
+          (setq cluster "cluster"
+                primary shadow-system-name
+                regexp (shadow-regexp-superquote primary)
+                mocked-input `(,cluster ,primary ,regexp))
+          (call-interactively 'shadow-define-cluster)
+          (should
+           (string-equal
+            (shadow-cluster-name (shadow-get-cluster cluster)) cluster))
+          (should
+           (string-equal
+            (shadow-cluster-primary (shadow-get-cluster cluster)) primary))
+          (should
+           (string-equal
+            (shadow-cluster-regexp (shadow-get-cluster cluster)) regexp))
+          (should-not (shadow-get-cluster "non-existent-cluster-name"))
+
+          ;; Test `shadow-set-cluster' and `make-shadow-cluster'.
+          (shadow-set-cluster cluster primary regexp)
+          (should
+           (equal (shadow-get-cluster cluster)
+                  (make-shadow-cluster
+                   :name cluster :primary primary :regexp regexp)))
+
+          ;; The primary must be either `shadow-system-name', or a remote file.
+          (setq ;; The second "cluster" is wrong.
+                mocked-input `(,cluster ,cluster ,primary ,regexp))
+          (with-current-buffer (messages-buffer)
+            (narrow-to-region (point-max) (point-max)))
+          (call-interactively 'shadow-define-cluster)
+          (should
+           (string-match
+            (regexp-quote "Not a valid primary!")
+            (with-current-buffer (messages-buffer) (buffer-string))))
+          ;; The first cluster definition is still valid.
+          (should
+           (string-equal
+            (shadow-cluster-name (shadow-get-cluster cluster)) cluster))
+          (should
+           (string-equal
+            (shadow-cluster-primary (shadow-get-cluster cluster)) primary))
+          (should
+           (string-equal
+            (shadow-cluster-regexp (shadow-get-cluster cluster)) regexp))
+
+          ;; The regexp must match the primary name.
+          (setq ;; The second "cluster" is wrong.
+                mocked-input `(,cluster ,primary ,cluster ,regexp))
+          (with-current-buffer (messages-buffer)
+            (narrow-to-region (point-max) (point-max)))
+          (call-interactively 'shadow-define-cluster)
+          (should
+           (string-match
+            (regexp-quote "Regexp doesn't include the primary host!")
+            (with-current-buffer (messages-buffer) (buffer-string))))
+          ;; The first cluster definition is still valid.
+          (should
+           (string-equal
+            (shadow-cluster-name (shadow-get-cluster cluster)) cluster))
+          (should
+           (string-equal
+            (shadow-cluster-primary (shadow-get-cluster cluster)) primary))
+          (should
+           (string-equal
+            (shadow-cluster-regexp (shadow-get-cluster cluster)) regexp))
+
+          ;; Redefine the cluster.
+          (setq primary
+                (file-remote-p shadow-test-remote-temporary-file-directory)
+                regexp (shadow-regexp-superquote primary)
+                mocked-input `(,cluster ,primary ,regexp))
+          (call-interactively 'shadow-define-cluster)
+          (should
+           (string-equal
+            (shadow-cluster-name (shadow-get-cluster cluster)) cluster))
+          (should
+           (string-equal
+            (shadow-cluster-primary (shadow-get-cluster cluster)) primary))
+          (should
+           (string-equal
+            (shadow-cluster-regexp (shadow-get-cluster cluster)) regexp))
+
+          ;; Test `shadow-set-cluster' and `make-shadow-cluster'.
+          (shadow-set-cluster cluster primary regexp)
+          (should
+           (equal (shadow-get-cluster cluster)
+                  (make-shadow-cluster
+                   :name cluster :primary primary :regexp regexp))))
+
+      ;; Cleanup.
+      (with-current-buffer (messages-buffer) (widen))
+      (when (file-exists-p shadow-info-file)
+        (delete-file shadow-info-file))
+      (when (file-exists-p shadow-todo-file)
+        (delete-file shadow-todo-file)))))
+
+(ert-deftest shadow-test01-sites ()
+  "Check site definitions.
+Per definition, all files are identical on the different hosts of
+a cluster (or site).  This is not tested here; it must be
+guaranteed by the originator of a cluster definition."
+  (skip-unless (file-remote-p shadow-test-remote-temporary-file-directory))
+
+  (let ((shadow-info-file shadow-test-info-file)
+        (shadow-todo-file shadow-test-todo-file)
+        shadow-clusters
+        cluster1 cluster2 primary1 primary2 regexp1 regexp2 mocked-input)
+    (unwind-protect
+        ;; We must mock `read-from-minibuffer' and `read-string', in
+        ;; order to avoid interactive arguments.
+        (cl-letf* (((symbol-function 'read-from-minibuffer)
+                    (lambda (&rest args) (pop mocked-input)))
+                   ((symbol-function 'read-string)
+                    (lambda (&rest args) (pop mocked-input))))
+
+          ;; Cleanup.
+          (when (file-exists-p shadow-info-file)
+            (delete-file shadow-info-file))
+          (when (file-exists-p shadow-todo-file)
+            (delete-file shadow-todo-file))
+
+          ;; Define a cluster.
+          (setq cluster1 "cluster1"
+                primary1 shadow-system-name
+                regexp1 (shadow-regexp-superquote primary1))
+          (shadow-set-cluster cluster1 primary1 regexp1)
+
+          ;; A site is either a cluster identification, or a primary host.
+          (should (string-equal cluster1 (shadow-site-name cluster1)))
+          (should (string-equal primary1 (shadow-name-site primary1)))
+          (should
+           (string-equal (format "/%s:" cluster1) (shadow-name-site cluster1)))
+          (should (string-equal (system-name) (shadow-site-name primary1)))
+          (should
+           (string-equal
+            (file-remote-p shadow-test-remote-temporary-file-directory)
+            (shadow-name-site
+             (file-remote-p shadow-test-remote-temporary-file-directory))))
+          (should
+           (string-equal
+            (file-remote-p shadow-test-remote-temporary-file-directory)
+            (shadow-site-name
+             (file-remote-p shadow-test-remote-temporary-file-directory))))
+
+          (should (equal (shadow-site-cluster cluster1)
+                         (shadow-get-cluster cluster1)))
+          (should (equal (shadow-site-cluster (shadow-name-site cluster1))
+                         (shadow-get-cluster cluster1)))
+          (should (equal (shadow-site-cluster primary1)
+                         (shadow-get-cluster cluster1)))
+          (should (equal (shadow-site-cluster (shadow-site-name primary1))
+                         (shadow-get-cluster cluster1)))
+          (should (string-equal (shadow-site-primary cluster1) primary1))
+          (should (string-equal (shadow-site-primary primary1) primary1))
+
+          ;; `shadow-read-site' accepts "cluster", "/cluster:",
+          ;; "system", "/system:".  It shall reject bad site names.
+          (setq mocked-input
+                `(,cluster1 ,(shadow-name-site cluster1)
+                  ,primary1 ,(shadow-site-name primary1)
+                  ,shadow-system-name "" "bad" "/bad:"))
+          (should (string-equal (shadow-read-site) cluster1))
+          (should (string-equal (shadow-read-site) (shadow-name-site cluster1)))
+          (should (string-equal (shadow-read-site) primary1))
+          (should (string-equal (shadow-read-site) (shadow-site-name primary1)))
+          (should (string-equal (shadow-read-site) shadow-system-name))
+          (should-not (shadow-read-site)) ; ""
+          (should-not (shadow-read-site)) ; "bad"
+          (should-not (shadow-read-site)) ; "/bad:"
+          (should-error (shadow-read-site)) ; no input at all
+
+          ;; Define a second cluster.
+          (setq cluster2 "cluster2"
+                primary2
+                (file-remote-p shadow-test-remote-temporary-file-directory)
+                regexp2 (format "^\\(%s\\|%s\\)$" shadow-system-name primary2))
+          (shadow-set-cluster cluster2 primary2 regexp2)
+
+          ;; `shadow-site-match' shall know all different kind of site names.
+          (should (shadow-site-match cluster1 cluster1))
+          (should (shadow-site-match primary1 primary1))
+          (should (shadow-site-match cluster1 primary1))
+          (should (shadow-site-match primary1 cluster1))
+          (should (shadow-site-match cluster2 cluster2))
+          (should (shadow-site-match primary2 primary2))
+          (should (shadow-site-match cluster2 primary2))
+          (should (shadow-site-match primary2 cluster2))
+
+          ;; The regexp of `cluster2' matches the primary of
+          ;; `cluster1'.  Not vice versa.
+          (should (shadow-site-match cluster2 cluster1))
+          (should-not (shadow-site-match cluster1 cluster2))
+
+          ;; If we use the primaries of a cluster, it doesn't match.
+          (should-not
+           (shadow-site-match (shadow-site-primary cluster2) cluster1))
+          (should-not
+           (shadow-site-match (shadow-site-primary cluster1) cluster2)))
+
+      ;; Cleanup.
+      (when (file-exists-p shadow-info-file)
+        (delete-file shadow-info-file))
+      (when (file-exists-p shadow-todo-file)
+        (delete-file shadow-todo-file)))))
+
+(ert-deftest shadow-test02-files ()
+  "Check file manipulation functions."
+  (skip-unless (file-remote-p shadow-test-remote-temporary-file-directory))
+
+  (let ((shadow-info-file shadow-test-info-file)
+        (shadow-todo-file shadow-test-todo-file)
+        shadow-clusters
+        cluster primary regexp file hup)
+    (unwind-protect
+        (progn
+          ;; Cleanup.
+          (when (file-exists-p shadow-info-file)
+            (delete-file shadow-info-file))
+          (when (file-exists-p shadow-todo-file)
+            (delete-file shadow-todo-file))
+
+          ;; Define a cluster.
+          (setq cluster "cluster"
+                primary shadow-system-name
+                regexp (shadow-regexp-superquote primary)
+                file (make-temp-name
+                      (expand-file-name
+                       "shadowfile-tests" temporary-file-directory)))
+          (shadow-set-cluster cluster primary regexp)
+
+          ;; The constant structure to compare with.
+          (setq hup (make-tramp-file-name :host (system-name) :localname file))
+
+          ;; The structure a local file is transformed in.
+          (should (equal (shadow-parse-name file) hup))
+          (should (equal (shadow-parse-name (concat "/" cluster ":" file)) hup))
+          (should (equal (shadow-parse-name (concat primary file)) hup))
+
+          ;; A local file name is kept.
+          (should
+           (string-equal (shadow-local-file file) file))
+          ;; A file on this cluster is also local.
+          (should
+           (string-equal
+            (shadow-local-file (concat "/" cluster ":" file)) file))
+          ;; A file on the primary host is also local.
+          (should
+           (string-equal (shadow-local-file (concat primary file)) file))
+
+          ;; Redefine the cluster.
+          (setq primary
+                (file-remote-p shadow-test-remote-temporary-file-directory)
+                regexp (shadow-regexp-superquote primary))
+          (shadow-set-cluster cluster primary regexp)
+
+          ;; The structure of the local file is still the same.
+          (should (equal (shadow-parse-name file) hup))
+          ;; The cluster name must be used.
+          (setf (tramp-file-name-host hup) cluster)
+          (should (equal (shadow-parse-name (concat "/" cluster ":" file)) hup))
+          ;; The structure of a remote file is different.
+          (should
+           (equal (shadow-parse-name (concat primary file))
+                  (tramp-dissect-file-name (concat primary file))))
+
+          ;; A local file is still local.
+          (should (shadow-local-file file))
+          ;; A file on this cluster is not local.
+          (should-not (shadow-local-file (concat "/" cluster ":" file)))
+          ;; A file on the primary host is not local.
+          (should-not (shadow-local-file (concat primary file)))
+          ;; There's no error on wrong FILE.
+          (should-not (shadow-local-file nil)))
+
+      ;; Cleanup.
+      (when (file-exists-p shadow-info-file)
+        (delete-file shadow-info-file))
+      (when (file-exists-p shadow-todo-file)
+        (delete-file shadow-todo-file)))))
+
+(ert-deftest shadow-test03-expand-cluster-in-file-name ()
+  "Check canonical file name of a cluster or site."
+  (skip-unless (file-remote-p shadow-test-remote-temporary-file-directory))
+
+  (let ((shadow-info-file shadow-test-info-file)
+        (shadow-todo-file shadow-test-todo-file)
+        shadow-clusters
+        cluster primary regexp file1 file2)
+    (unwind-protect
+        (progn
+          ;; Cleanup.
+          (when (file-exists-p shadow-info-file)
+            (delete-file shadow-info-file))
+          (when (file-exists-p shadow-todo-file)
+            (delete-file shadow-todo-file))
+
+          ;; Define a cluster.
+          (setq cluster "cluster"
+                primary shadow-system-name
+                regexp (shadow-regexp-superquote primary))
+          (shadow-set-cluster cluster primary regexp)
+
+          (setq file1
+                (make-temp-name
+                 (expand-file-name "shadowfile-tests" temporary-file-directory))
+                file2
+                (make-temp-name
+                 (expand-file-name
+                  "shadowfile-tests"
+                  shadow-test-remote-temporary-file-directory)))
+
+          ;; A local file name is kept.
+          (should
+           (string-equal (shadow-expand-cluster-in-file-name file1) file1))
+          ;; A remote file is kept.
+          (should
+           (string-equal (shadow-expand-cluster-in-file-name file2) file2))
+          ;; A cluster name is expanded to the primary name.
+          (should
+           (string-equal
+            (shadow-expand-cluster-in-file-name (format "/%s:%s" cluster file1))
+            (shadow-expand-cluster-in-file-name (concat primary file1))))
+          ;; A primary name is expanded if it is a local file name.
+          (should
+           (string-equal
+            (shadow-expand-cluster-in-file-name (concat primary file1)) file1))
+
+          ;; Redefine the cluster.
+          (setq primary
+                (file-remote-p shadow-test-remote-temporary-file-directory)
+                regexp (shadow-regexp-superquote primary))
+          (shadow-set-cluster cluster primary regexp)
+
+          ;; A cluster name is expanded to the primary name.
+          (should
+           (string-equal
+            (shadow-expand-cluster-in-file-name (format "/%s:%s" cluster file1))
+            (shadow-expand-cluster-in-file-name (concat primary file1))))
+          ;; A primary name is not expanded if it isn't is a local file name.
+          (should
+           (string-equal
+            (shadow-expand-cluster-in-file-name (concat primary file1))
+            (concat primary file1))))
+
+      ;; Cleanup.
+      (when (file-exists-p shadow-info-file)
+        (delete-file shadow-info-file))
+      (when (file-exists-p shadow-todo-file)
+        (delete-file shadow-todo-file)))))
+
+(ert-deftest shadow-test04-contract-file-name ()
+  "Check canonical file name of a cluster or site."
+  (skip-unless (file-remote-p shadow-test-remote-temporary-file-directory))
+
+  (let ((shadow-info-file shadow-test-info-file)
+        (shadow-todo-file shadow-test-todo-file)
+        shadow-clusters
+        cluster primary regexp file)
+    (unwind-protect
+        (progn
+          ;; Cleanup.
+          (when (file-exists-p shadow-info-file)
+            (delete-file shadow-info-file))
+          (when (file-exists-p shadow-todo-file)
+            (delete-file shadow-todo-file))
+
+          ;; Define a cluster.
+          (setq cluster "cluster"
+                primary shadow-system-name
+                regexp (shadow-regexp-superquote primary)
+                file (make-temp-name
+                      (expand-file-name
+                       "shadowfile-tests" temporary-file-directory)))
+          (shadow-set-cluster cluster primary regexp)
+
+          ;; The cluster name is prepended for local files.
+          (should
+           (string-equal
+            (shadow-contract-file-name file) (concat "/cluster:" file)))
+          ;; A cluster file name is preserved.
+          (should
+           (string-equal
+            (shadow-contract-file-name (concat "/cluster:" file))
+            (concat "/cluster:" file)))
+          ;; `shadow-system-name' is mapped to the cluster.
+          (should
+           (string-equal
+            (shadow-contract-file-name (concat shadow-system-name file))
+            (concat "/cluster:" file)))
+
+          ;; Redefine the cluster.
+          (setq primary
+                (file-remote-p shadow-test-remote-temporary-file-directory)
+                regexp (shadow-regexp-superquote primary))
+          (shadow-set-cluster cluster primary regexp)
+
+          ;; A remote file name is mapped to the cluster.
+          (should
+           (string-equal
+            (shadow-contract-file-name
+             (concat
+              (file-remote-p shadow-test-remote-temporary-file-directory) file))
+            (concat "/cluster:" file))))
+
+      ;; Cleanup.
+      (when (file-exists-p shadow-info-file)
+        (delete-file shadow-info-file))
+      (when (file-exists-p shadow-todo-file)
+        (delete-file shadow-todo-file)))))
+
+(ert-deftest shadow-test05-file-match ()
+  "Check `shadow-same-site' and `shadow-file-match'."
+  (skip-unless (file-remote-p shadow-test-remote-temporary-file-directory))
+
+  (let ((shadow-info-file shadow-test-info-file)
+        (shadow-todo-file shadow-test-todo-file)
+        shadow-clusters
+        cluster primary regexp file)
+    (unwind-protect
+        (progn
+          ;; Cleanup.
+          (when (file-exists-p shadow-info-file)
+            (delete-file shadow-info-file))
+          (when (file-exists-p shadow-todo-file)
+            (delete-file shadow-todo-file))
+
+          ;; Define a cluster.
+          (setq cluster "cluster"
+                primary shadow-system-name
+                regexp (shadow-regexp-superquote primary)
+                file (make-temp-name
+                      (expand-file-name
+                       "shadowfile-tests" temporary-file-directory)))
+          (shadow-set-cluster cluster primary regexp)
+
+          (should (shadow-same-site (shadow-parse-name "/cluster:") file))
+          (should
+           (shadow-same-site (shadow-parse-name shadow-system-name) file))
+          (should (shadow-same-site (shadow-parse-name file) file))
+
+          (should
+           (shadow-file-match
+            (shadow-parse-name (concat "/cluster:" file)) file))
+          (should
+           (shadow-file-match
+            (shadow-parse-name (concat shadow-system-name file)) file))
+          (should (shadow-file-match (shadow-parse-name file) file))
+
+          ;; Redefine the cluster.
+          (setq primary
+                (file-remote-p shadow-test-remote-temporary-file-directory)
+                regexp (shadow-regexp-superquote primary))
+          (shadow-set-cluster cluster primary regexp)
+
+          (should
+           (shadow-file-match
+            (shadow-parse-name
+             (concat
+              (file-remote-p shadow-test-remote-temporary-file-directory)
+              file))
+            file)))
+
+      ;; Cleanup.
+      (when (file-exists-p shadow-info-file)
+        (delete-file shadow-info-file))
+      (when (file-exists-p shadow-todo-file)
+        (delete-file shadow-todo-file)))))
+
+(ert-deftest shadow-test06-literal-groups ()
+  "Check literal group definitions."
+  (let ((shadow-info-file shadow-test-info-file)
+        (shadow-todo-file shadow-test-todo-file)
+        shadow-clusters shadow-literal-groups
+        cluster1 cluster2 primary regexp file1 file2 mocked-input)
+    (unwind-protect
+        ;; We must mock `read-from-minibuffer' and `read-string', in
+        ;; order to avoid interactive arguments.
+        (cl-letf* (((symbol-function 'read-from-minibuffer)
+                    (lambda (&rest args) (pop mocked-input)))
+                   ((symbol-function 'read-string)
+                    (lambda (&rest args) (pop mocked-input))))
+
+          ;; Cleanup.
+          (when (file-exists-p shadow-info-file)
+            (delete-file shadow-info-file))
+          (when (file-exists-p shadow-todo-file)
+            (delete-file shadow-todo-file))
+
+          ;; Define clusters.
+          (setq cluster1 "cluster1"
+                primary shadow-system-name
+                regexp (shadow-regexp-superquote primary))
+          (shadow-set-cluster cluster1 primary regexp)
+
+          (setq cluster2 "cluster2"
+                primary
+                (file-remote-p shadow-test-remote-temporary-file-directory)
+                regexp (format "^\\(%s\\|%s\\)$" shadow-system-name primary))
+          (shadow-set-cluster cluster2 primary regexp)
+
+          ;; Define a literal group.
+          (setq file1
+                (make-temp-name
+                 (expand-file-name "shadowfile-tests" temporary-file-directory))
+                file2
+                (make-temp-name
+                 (expand-file-name
+                  "shadowfile-tests"
+                  shadow-test-remote-temporary-file-directory))
+                mocked-input `(,cluster1 ,file1 ,cluster2 ,file2 ,(kbd "RET")))
+          (with-temp-buffer
+            (setq-local buffer-file-name file1)
+            (call-interactively 'shadow-define-literal-group))
+
+          ;; `shadow-literal-groups' is a list of lists.
+          (should (consp shadow-literal-groups))
+          (should (consp (car shadow-literal-groups)))
+          (should-not (cdr shadow-literal-groups))
+
+          (should (member (format "/%s:%s" cluster1 (file-local-name file1))
+                          (car shadow-literal-groups)))
+          (should (member (format "/%s:%s" cluster2 (file-local-name file2))
+                          (car shadow-literal-groups))))
+
+      ;; Cleanup.
+      (when (file-exists-p shadow-info-file)
+        (delete-file shadow-info-file))
+      (when (file-exists-p shadow-todo-file)
+        (delete-file shadow-todo-file)))))
+
+(ert-deftest shadow-test07-regexp-groups ()
+  "Check regexp group definitions."
+  (let ((shadow-info-file shadow-test-info-file)
+        (shadow-todo-file shadow-test-todo-file)
+        shadow-clusters shadow-regexp-groups
+        cluster1 cluster2 primary regexp file mocked-input)
+    (unwind-protect
+        ;; We must mock `read-from-minibuffer' and `read-string', in
+        ;; order to avoid interactive arguments.
+        (cl-letf* (((symbol-function 'read-from-minibuffer)
+                    (lambda (&rest args) (pop mocked-input)))
+                   ((symbol-function 'read-string)
+                    (lambda (&rest args) (pop mocked-input))))
+
+          ;; Cleanup.
+          (when (file-exists-p shadow-info-file)
+            (delete-file shadow-info-file))
+          (when (file-exists-p shadow-todo-file)
+            (delete-file shadow-todo-file))
+
+          ;; Define clusters.
+          (setq cluster1 "cluster1"
+                primary shadow-system-name
+                regexp (shadow-regexp-superquote primary))
+          (shadow-set-cluster cluster1 primary regexp)
+
+          (setq cluster2 "cluster2"
+                primary
+                (file-remote-p shadow-test-remote-temporary-file-directory)
+                regexp (format "^\\(%s\\|%s\\)$" shadow-system-name primary))
+          (shadow-set-cluster cluster2 primary regexp)
+
+          ;; Define a regexp group.
+          (setq file
+                (make-temp-name
+                 (expand-file-name "shadowfile-tests" temporary-file-directory))
+                mocked-input `(,(shadow-regexp-superquote file)
+                               ,cluster1 ,cluster2 ,(kbd "RET")))
+          (with-temp-buffer
+            (setq-local buffer-file-name nil)
+            (call-interactively 'shadow-define-regexp-group))
+
+          ;; `shadow-regexp-groups' is a list of lists.
+          (should (consp shadow-regexp-groups))
+          (should (consp (car shadow-regexp-groups)))
+          (should-not (cdr shadow-regexp-groups))
+
+          (should
+           (member
+            (concat
+             (shadow-site-primary cluster1) (shadow-regexp-superquote file))
+            (car shadow-regexp-groups)))
+          (should
+           (member
+            (concat
+             (shadow-site-primary cluster2) (shadow-regexp-superquote file))
+            (car shadow-regexp-groups))))
+
+      ;; Cleanup.
+      (when (file-exists-p shadow-info-file)
+        (delete-file shadow-info-file))
+      (when (file-exists-p shadow-todo-file)
+        (delete-file shadow-todo-file)))))
+
+(ert-deftest shadow-test08-shadow-todo ()
+  "Check that needed shadows are added to todo."
+  (let ((backup-inhibited t)
+        (shadow-info-file shadow-test-info-file)
+        (shadow-todo-file shadow-test-todo-file)
+        (shadow-inhibit-message t)
+        shadow-clusters shadow-literal-groups shadow-regexp-groups
+        shadow-files-to-copy
+        cluster1 cluster2 primary regexp file)
+    (unwind-protect
+        (progn
+          ;; Cleanup.
+          (when (file-exists-p shadow-info-file)
+            (delete-file shadow-info-file))
+          (when (file-exists-p shadow-todo-file)
+            (delete-file shadow-todo-file))
+
+          ;; Define clusters.
+          (setq cluster1 "cluster1"
+                primary shadow-system-name
+                regexp (shadow-regexp-superquote primary))
+          (shadow-set-cluster cluster1 primary regexp)
+
+          (setq cluster2 "cluster2"
+                primary
+                (file-remote-p shadow-test-remote-temporary-file-directory)
+                regexp (shadow-regexp-superquote primary))
+          (shadow-set-cluster cluster2 primary regexp)
+
+          ;; Define a literal group.
+          (setq file
+                (make-temp-name
+                 (expand-file-name "shadowfile-tests" temporary-file-directory))
+                shadow-literal-groups
+                `((,(concat "/cluster1:" file) ,(concat "/cluster2:" file))))
+
+          ;; Save file from "cluster1" definition.
+          (with-temp-buffer
+            (setq buffer-file-name file)
+            (insert "foo")
+            (save-buffer))
+          (should
+           (member
+            (cons file (shadow-contract-file-name (concat "/cluster2:" file)))
+            shadow-files-to-copy))
+
+          ;; Save file from "cluster2" definition.
+          (with-temp-buffer
+            (setq buffer-file-name (concat (shadow-site-primary cluster2) file))
+            (insert "foo")
+            (save-buffer))
+          (should
+           (member
+            (cons
+             (concat (shadow-site-primary cluster2) file)
+             (shadow-contract-file-name (concat "/cluster1:" file)))
+            shadow-files-to-copy))
+
+          ;; Define a regexp group.
+          (setq shadow-files-to-copy nil
+                shadow-regexp-groups
+                `((,(concat (shadow-site-primary cluster1)
+                            (shadow-regexp-superquote file))
+                   ,(concat (shadow-site-primary cluster2)
+                            (shadow-regexp-superquote file)))))
+
+          ;; Save file from "cluster1" definition.
+          (with-temp-buffer
+            (setq buffer-file-name file)
+            (insert "foo")
+            (save-buffer))
+          (should
+           (member
+            (cons file (shadow-contract-file-name (concat "/cluster2:" file)))
+            shadow-files-to-copy))
+
+          ;; Save file from "cluster2" definition.
+          (with-temp-buffer
+            (setq buffer-file-name (concat (shadow-site-primary cluster2) file))
+            (insert "foo")
+            (save-buffer))
+          (should
+           (member
+            (cons
+             (concat (shadow-site-primary cluster2) file)
+             (shadow-contract-file-name (concat "/cluster1:" file)))
+            shadow-files-to-copy)))
+
+      ;; Cleanup.
+      (when (file-exists-p shadow-info-file)
+        (delete-file shadow-info-file))
+      (when (file-exists-p shadow-todo-file)
+        (delete-file shadow-todo-file))
+      (when (file-exists-p file)
+        (delete-file file))
+      (when (file-exists-p (concat (shadow-site-primary cluster2) file))
+        (delete-file (concat (shadow-site-primary cluster2) file))))))
+
+(ert-deftest shadow-test09-shadow-copy-files ()
+  "Check that needed shadow files are copied."
+  (let ((backup-inhibited t)
+        (shadow-info-file shadow-test-info-file)
+        (shadow-todo-file shadow-test-todo-file)
+        (shadow-inhibit-message t)
+        (shadow-noquery t)
+        shadow-clusters shadow-files-to-copy
+        cluster1 cluster2 primary regexp file mocked-input)
+    (unwind-protect
+        (progn
+          ;; Cleanup.
+          (when (file-exists-p shadow-info-file)
+            (delete-file shadow-info-file))
+          (when (file-exists-p shadow-todo-file)
+            (delete-file shadow-todo-file))
+          (when (buffer-live-p shadow-todo-buffer)
+            (with-current-buffer shadow-todo-buffer (erase-buffer)))
+
+          ;; Define clusters.
+          (setq cluster1 "cluster1"
+                primary shadow-system-name
+                regexp (shadow-regexp-superquote primary))
+          (shadow-set-cluster cluster1 primary regexp)
+
+          (setq cluster2 "cluster2"
+                primary
+                (file-remote-p shadow-test-remote-temporary-file-directory)
+                regexp (shadow-regexp-superquote primary))
+          (shadow-set-cluster cluster2 primary regexp)
+
+          ;; Define files to copy.
+          (setq file
+                (make-temp-name
+                 (expand-file-name "shadowfile-tests" temporary-file-directory))
+                shadow-literal-groups
+                `((,(concat "/cluster1:" file) ,(concat "/cluster2:" file)))
+                shadow-regexp-groups
+                `((,(concat (shadow-site-primary cluster1)
+                            (shadow-regexp-superquote file))
+                   ,(concat (shadow-site-primary cluster2)
+                            (shadow-regexp-superquote file))))
+                mocked-input `(,(concat (shadow-site-primary cluster2) file)
+                               ,file))
+
+          ;; Save files.
+          (with-temp-buffer
+            (setq buffer-file-name file)
+            (insert "foo")
+            (save-buffer))
+          (with-temp-buffer
+            (setq buffer-file-name (concat (shadow-site-primary cluster2) file))
+            (insert "foo")
+            (save-buffer))
+
+          ;; We must mock `write-region', in order to check proper
+          ;; action.
+          (add-function
+           :before (symbol-function 'write-region)
+           (lambda (&rest args)
+             (when (and (buffer-file-name) mocked-input)
+               (should (equal (buffer-file-name) (pop mocked-input)))))
+           '((name . "write-region-mock")))
+
+          ;; Copy the files.
+          (shadow-copy-files 'noquery)
+          (should-not shadow-files-to-copy)
+          (with-current-buffer shadow-todo-buffer
+            (goto-char (point-min))
+            (should
+             (looking-at (regexp-quote "(setq shadow-files-to-copy nil)")))))
+
+      ;; Cleanup.
+      (remove-function (symbol-function 'write-region) "write-region-mock")
+      (when (file-exists-p shadow-info-file)
+        (delete-file shadow-info-file))
+      (when (file-exists-p shadow-todo-file)
+        (delete-file shadow-todo-file))
+      (when (file-exists-p file)
+        (delete-file file))
+      (when (file-exists-p (concat (shadow-site-primary cluster2) file))
+        (delete-file (concat (shadow-site-primary cluster2) file))))))
+
+(defun shadowfile-test-all (&optional interactive)
+  "Run all tests for \\[shadowfile]."
+  (interactive "p")
+  (if interactive
+      (ert-run-tests-interactively "^shadowfile-")
+    (ert-run-tests-batch "^shadowfile-")))
+
+(let ((shadow-info-file shadow-test-info-file)
+      (shadow-todo-file shadow-test-todo-file))
+  (shadow-initialize))
+
+(provide 'shadowfile-tests)
+;;; shadowfile-tests.el ends here