fakir.el

;;; fakir.el --- fakeing bits of Emacs -*- lexical-binding: t -*-
;; Copyright (C) 2012  Nic Ferrier

;; Author: Nic Ferrier <nferrier@ferrier.me.uk>
;; Maintainer: Nic Ferrier <nferrier@ferrier.me.uk>
;; Created: 17th March 2012
;; Version: 0.0.10
;; Keywords: lisp, tools

;; This file is NOT part of GNU Emacs.

;; 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:
;;
;; This is an collection of tools to make testing Emacs core functions
;; easier.
;;
;;; Source code
;;
;; fakir's code can be found here:
;;   http://github.com/nicferrier/fakir

;;; Style note
;;
;; This codes uses the Emacs style of:
;;
;;    fakir--private-function
;;
;; for private functions and macros.


;;; Code:

(require 'ert)
(eval-when-compile (require 'cl))


;; A little support code - not sure I can be bothered to package this
;; seperately

(defmacro* flet-overrides (predicate
			   bindings
			   &rest form)
  "Override functions only when an argument tests true.

PREDICATE is some test to be applied to a specified argument
of each bound FUNC to decide whether to execute the overridden
code or the existing code.

For each function, TEST-ARG specifies the name of the argument in
the ARGLIST which will be passed to the PREDICATE.

BODY defines the code to be run for the specified FUNC when the
PREDICATE is `t' for the TEST-ARG.

This is really useful when you want to mock a set of functions
that operate on a particular type, processes for example:

  (flet-overrides fake-process-p
     ((process-buffer process (process)
        (get-buffer-create \"\"))
      (process-status process (process)
        \"run\")
      (delete-process process (process)
        t)
      (set-process-buffer process (process buffer)
        nil))
    ;; Code under test
    ...)

\(fn PREDICATE ((FUNC TEST-ARG ARGLIST BODY...) ...) FORM...)"
  (declare (indent defun))
  (let*
      ((flets
	(loop
	 for i in bindings
	 collect
	 (destructuring-bind (name test-arg args &rest body) i
	   (let ((saved-func-namev (make-symbol "saved-func-name")))
	     (let ((saved-func-namev
		    (intern (format "saved-func-%s"
				    (symbol-name name)))))
	       `(,name ,args
		       (if (not (,predicate ,test-arg))
			   (funcall ,saved-func-namev ,@args)
			 ,@body)))))))
       (lets
	(loop
	 for i in bindings
	 collect
	 (destructuring-bind (name test-arg args &rest body) i
	   (let ((saved-func-namev (make-symbol "saved-func-name")))
	     (let ((saved-func-namev
		    (intern (format "saved-func-%s"
				    (symbol-name name)))))
	       `(,saved-func-namev
		 (symbol-function (quote ,name)))))))))
    `(let ,lets
       (flet ,flets
	 ,@form))))

(ert-deftest flet-overrides ()
  "Test the flet-override stuff."
  (flet ((my-test (x)
		  (and
		   (listp x)
		   (let ((v (car x)))
		     (eq :object v))))
	 (my-func (x y)
		  (format "strings: %s %s" x y))
	 (my-proc (z)
		  (* 2 x)))
    (flet-overrides
      my-test ; the type predicate we'll use
      ((my-func a (a b)
		(+ (cadr a) b))
       (my-proc y (x y)
		(+ 10 y)))
      (should
       (equal
	'("strings: nic caroline" 7)
	(list
	 ;; This call doesn't match the predicate
	 (my-func "nic" "caroline")
	 ;; This call does match the predicate
	 (my-func '(:object 5) 2)))))))


;; Mocking processes

(defvar fakir-mock-process-require-specified-buffer nil
  "Tell `fakir-mock-process' that you require a buffer to be set.

This is used, for example, to make `elnode--filter' testing work
properly. Normally, tests do not need to set the process-buffer
directly, they can just expect it to be there. `elnode--filter',
though, needs to set the process-buffer to work properly.")


(defun fakir--make-hash-table (alist)
  "Make a hash table from the ALIST.

The ALIST looks like a let-list."
  (let ((bindings (make-hash-table :test 'equal)))
    (loop for f in (append
                    (list (list :fakir-mock-process t))
                    alist)
       do
         (cond
           ((and f (listp f))
            (puthash (car f) (cadr f) bindings))
           (t
            (puthash f nil bindings))))
    bindings))

(ert-deftest fakir--make-hash-table ()
  "Test hash table construction."
  (let ((h (fakir--make-hash-table '((a 10)
                                     (b 20)
                                     (fakir-alist-value "is a string")
                                     fakir-single-value
                                     :self-evaling-symbol-as-well))))
    (should (equal 10 (gethash 'a h)))
    (should (equal 20 (gethash 'b h)))
    (should (equal nil (gethash 'fakir-single-value h)))
    (should (equal nil (gethash ':self-evaling-symbol-as-well h)))))

(defun fakir--get-or-create-buf (pvbuf pvvar &optional specified-buf)
  "Special get or create to support the process mocking.

PVBUF is a, possibly existing, buffer reference.  If nil then we
create the buffer.

PVVAR is a hashtable of properties, possibly containing the
`:buffer' property which specifies a string to be used as the
content of the buffer.

SPECIFIED-BUF is an optional buffer to use instead of a dummy
created one."
  (if (bufferp pvbuf)
      pvbuf
    (setq pvbuf
	  (if fakir-mock-process-require-specified-buffer
	      (if (bufferp specified-buf)
		  specified-buf
		nil)
	    (or specified-buf
		(get-buffer-create
		 (generate-new-buffer-name
		  "* fakir mock proc buf *")))))
    ;; If we've got a buffer value then insert it.
    (when (gethash :buffer pvvar)
      (with-current-buffer pvbuf
	(insert (gethash :buffer pvvar))))
    pvbuf))


(defmacro fakir-mock-process (process-symbol process-bindings &rest body)
  "Allow easier testing by mocking the process functions.

For example:

 (fakir-mock-process :fake
      (:elnode-http-params
       (:elnode-http-method \"GET\")
       (:elnode-http-query \"a=10\"))
   (should (equal 10 (elnode-http-param :fake \"a\"))))

Causes:

 (process-get :fake :elnode-http-method)

to always return \"GET\".

`process-put' is also remapped, currently to swallow any setting.

`process-buffer' is also remapped, to deliver the value of the
key `:buffer' if present and a dummy buffer otherwise.

`delete-process' is also remapped, to throw
`:mock-process-finished' to the catch called
`:mock-process-finished'.  You can implement your own catch to do
something with the `delete-process' event.

In normal circumstances, we return what the BODY returned."
  (declare
   (debug (sexp sexp &rest form))
   (indent defun))
  (let ((predfunc (make-symbol "predfunc"))
	(get-or-create-buf-func (make-symbol "getorcreatebuffunc"))
	(pvvar (make-symbol "pv"))
        (pvbuf (make-symbol "buf"))
        (result (make-symbol "result")))
    `(let
         ((,pvvar
           (fakir--make-hash-table
            (list ,@(loop for p in process-bindings
                       collect
                         (if (and p (listp p))
                             (list 'list `(quote ,(car p)) (cadr p))
                             (list 'cons `,p nil))))))
          ;; For assigning the result of the body
          ,result
          ;; Dummy buffer variable for the process - we fill this in
          ;; dynamically in 'process-buffer
          ,pvbuf)
       (flet ((,predfunc (object) (eq object ,process-symbol))
	      (,get-or-create-buf-func
	       (proc &optional specified-buf)
	       (setq ,pvbuf (fakir--get-or-create-buf
			     ,pvbuf
			     ,pvvar
			     specified-buf))))
	 ;; Rebind the process function interface
	 (flet-overrides ,predfunc
	   ((process-get proc (proc key) (gethash key ,pvvar))
	    (process-put proc (proc key value) (puthash key value ,pvvar))
	    (processp proc (proc) t)
	    (process-send-eof proc (proc) t)
	    (process-status proc (proc) 'fake)
	    (process-buffer proc (proc) (,get-or-create-buf-func proc))
	    (process-contact
	     proc (proc &optional arg)
	     (list "localhost" 8000))
	    (process-send-string
	     proc (proc str)
	     (with-current-buffer (,get-or-create-buf-func proc)
	       (save-excursion
		 (goto-char (point-max))
		 (insert str))))
	    (delete-process
	     proc (proc)
	     (throw
	      :mock-process-finished :mock-process-finished))
	    (set-process-buffer
	     proc (proc buffer)
	     (,get-or-create-buf-func proc buffer)))
	   (unwind-protect
	       (setq ,result
		     (catch :mock-process-finished
		       ,@body))
	     ;; Now clean up
	     (when (bufferp ,pvbuf)
	       (with-current-buffer ,pvbuf
		 (set-buffer-modified-p nil)
		 (kill-buffer ,pvbuf)))))))))

(defun fakir-test-mock-process ()
  "A very quick function to test mocking process macro."
  (let ((somevalue 30))
    (fakir-mock-process
      :fakeproc
      ((a 20)
       (:somevar 15)
       (:othervar somevalue))
      (let ((z 10))
	(let ((a "my string!!!"))
	  (setq a (process-get :fakeproc :somevar))
	  (list a (process-get :fakeproc :othervar)))))))

(ert-deftest fakir-mock-process ()
  "Basic test of the mock process."
  :tags '(unit)
  (let ((x (fakir-test-mock-process)))
    (should (equal '(15 30) x))))

(ert-deftest fakir-mock-process-delete ()
  "Test the delete handling."
  :tags '(unit)
  ;; delete-process causes the body to return :mock-process-finished
  (should
   (fakir-mock-process
     :fakeproc
     ((a 20)
      (:somevar "somevar"))
     (let ((x "a string of text"))
       (delete-process :fakeproc))))
  ;; How to use catch inside the BODY to handle delete-process
  (should
   (equal
    "the process finished"
    (fakir-mock-process
      :fakeproc
      ((a 20)
       (:somevar "somevar"))
      (let ((x "a string of text"))
	(when (eq :mock-process-finished
		  (catch :mock-process-finished
		    (delete-process :fakeproc)))
	  "the process finished"))))))

;; Time utils

(defun fakir-time-encode (time-str)
  "Encode the TIME-STR as an EmacsLisp time."
  ;; FIXME this should be part of Emacs probably; I've had to
  ;; implement this in Elnode as well
  (apply 'encode-time (parse-time-string time-str)))


;; A structure to represent a mock file

(defstruct fakir-file
  filename
  directory
  (content "")
  ;; obviously there should be all the state of the file here
  (mtime "Mon, Feb 27 2012 22:10:19 GMT"))

(defun fakir-file (&rest args)
  "Make a fakir-file, a struct."
  (apply 'make-fakir-file args))

(defun fakir--file-check (file)
  "Implements the type check for FILE is a `fakir--file'."
  (if (not (fakir-file-p file))
      (error "not an fakir--file")))

(defun fakir--file-fqn (file)
  "Return the fully qualified name of FILE, an `fakir--file'."
  (fakir--file-check file)
  (let* ((fqfn
          (concat
           (file-name-as-directory
            (fakir-file-directory file))
           (fakir-file-filename file))))
    fqfn))

(ert-deftest fakir--file-fqn ()
  "Test we can make fully qualified names for files."
  (let ((ef (make-fakir-file
             :filename "somefile"
             :directory "/home/dir")))
    (should (equal "/home/dir/somefile"
                   (fakir--file-fqn ef)))))

(defun fakir--file-mod-time (file &optional raw)
  "Return the encoded mtime of FILE, an `fakir--file'.

If RAW is t then return the raw value, a string."
  (fakir--file-check file)
  (if raw
      (fakir-file-mtime file)
    (fakir-time-encode (fakir-file-mtime file))))

(ert-deftest fakir--file-mod-time ()
  "Test that file mtimes are encoded properly."
  (let ((ef (make-fakir-file
             :filename "somefile"
             :directory "/home/dir"
             :mtime "Mon, Feb 27 2012 22:10:21 GMT")))
    (should (equal (fakir--file-mod-time ef)
                   '(20299 65357)))))

(defun fakir--file-attribs (file)
  "Return an answer as `file-attributes' for FILE.

Currently WE ONLY SUPPORT MODIFIED-TIME."
  (fakir--file-check file)
  (list t t t t t
        (fakir--file-mod-time file)))

(ert-deftest fakir--file-attribs ()
  "Test that we get back file attributes."
  (let ((ef (make-fakir-file
             :filename "somefile"
             :directory "/home/dir"
             :mtime "Mon, Feb 27 2012 22:10:21 GMT")))
    (should (equal
             (list t t t t t '(20299 65357))
             (fakir--file-attribs ef)))))

(defun fakir--file-home (file)
  "Return the home part of FILE or nil.

The home part of FILE is the part that is the home directory of
the user. If it's not a user FILE then it won't have a home
part."
  (fakir--file-check file)
  (let* ((fqn (fakir--file-fqn file))
         (home-root
          (save-match-data
            (when
                (string-match
                 "^\\(/home/[A-Za-z][A-Za-z0-9-]+\\)\\(/.*\\)*"
                 fqn)
              (match-string 1 fqn)))))
    home-root))

(ert-deftest fakir--file-home ()
  "Test the home root stuff."
  (let ((ef (make-fakir-file
             :filename "somefile"
             :directory "/home/dir"))
        (ef2 (make-fakir-file
             :filename "somefile"
             :directory "/var/dir"))
        (ef3 (make-fakir-file
              :filename "somefile"
              :directory "/home/dir/someddir")))
    (should (equal "/home/dir" (fakir--file-home ef)))
    (should (equal "/home/dir" (fakir--file-home ef3)))
    (should (equal nil (fakir--file-home ef2)))))

(defun fakir--file-exists-p (file-name fqfn)
  (equal fqfn file-name))

(defun fakir--expand-file-name (file-name home-root)
  "Simple implementation of .. and ~ handling for FILE-NAME."
  ;; tali713 recomended this as a replacement here
  ;; http://paste.lisp.org/display/128254
  (let* ((fqfn (if (string-match "^\\(~/\\|/\\).*" file-name)
                   file-name
                  (concat
                   (file-name-as-directory home-root) file-name)))
         (file-path (replace-regexp-in-string
                     "^~/\\(.\\)"
                     (concat
                      (file-name-as-directory home-root) "\\1")
                     fqfn))
         (path (split-string file-path "/" t))
         res)
    (while path
      (if (string= ".." (car path))
          (setq res (cdr res))
        (setq res
              (cons (car path) (if (consp res) res))))
      (setq path (cdr path)))
    (concat
     (when (equal ?\/ (elt file-path 0)) "/")
     (mapconcat 'identity (reverse res) "/"))))

(ert-deftest fakir--expand-file-name ()
  "Test expanding names to absolutes."
  (should
   (equal
    (fakir--expand-file-name
     "blah"
     "/home/emacsuser")
    "/home/emacsuser/blah"))
  (should
   (equal
    (fakir--expand-file-name
     "/home/emacsuser/bladh/qdqnwd/qwdqdq.1"
     "/home/emacsuser")
    "/home/emacsuser/bladh/qdqnwd/qwdqdq.1"))
  (should
   (equal
    (fakir--expand-file-name
     "/home/emacsuser/bladh/../qwdqdq.2"
     "/home/emacsuser")
    "/home/emacsuser/qwdqdq.2"))
  (should
   (equal
    (fakir--expand-file-name
     "qwdqdq.3"
     "/home")
    "/home/qwdqdq.3"))
  (should
   (equal
    (fakir--expand-file-name
     "/qwdqdq.4"
     "/home")
    "/qwdqdq.4"))
  (should
   (equal
    (fakir--expand-file-name
     "/home/emacsuser/bladh/../../../../../../qwdqdq.5"
     "/home")
    "/qwdqdq.5")))

(defun fakir--find-file (fakir-file)
  (let ((buf (get-buffer-create (fakir-file-filename fakir-file))))
    (with-current-buffer buf
      (insert (fakir-file-content fakir-file)))
    buf))

(ert-deftest fakir--find-file ()
  (let ((f (fakir-file :filename "README"
                       :directory "/home/fakir"
                       :content "This is a ReadMe file.")))
    (let ((buf (fakir--find-file f)))
      (unwind-protect
          (with-current-buffer buf
            (should
             (equal "This is a ReadMe file."
                    (buffer-substring (point-min) (point-max)))))
        (kill-buffer buf)))))

(defmacro fakir-mock-file (fakir-file &rest body)
  "Mock the filesystem with the FAKIR-FILE object.

The Emacs Lisp file operations are flet'd so that they operate on
the FAKIR-FILE.

For example:

 (fakir-mock-file (fakir-file
                     :filename \"README\"
                     :directory \"/home/emacs/fakir\")
    (expand-file-name \"~/fakir/README\"))

 => \"/home/emacs/fakir/README\"

The operations that are supported by the fleted functions are:
`file-attributes', `file-exists-p' and `expand-file-name'. Others
will be added as necessary."
  (declare (debug (sexp &rest form))
           (indent defun))
  (let ((fv (make-symbol "fakir-filev")))
    `(let*
         ((,fv ,fakir-file)
          (fqfn (fakir--file-fqn ,fv))
          (home-root (fakir--file-home ,fv))
          (default-directory home-root))
       (flet ((file-attributes
               (file-name)
               (fakir--file-attribs ,fv))
              (file-exists-p
               (file-name)
               (fakir--file-exists-p file-name fqfn))
              (expand-file-name
               (file-name &optional def-dir)
               (fakir--expand-file-name
                file-name
                (or def-dir home-root)))
              (find-file
               (file-name)
               (fakir--find-file ,fv))
              (find-file-noselect
               (file-name)
               (fakir--find-file ,fv)))
         ,@body))))

(ert-deftest fakir-mock-file ()
  "Test the mock file macro."
  (fakir-mock-file (make-fakir-file
                      :filename "somefile"
                      :directory "/home/test"
                      :content "This is a file."
                      :mtime "Mon, Feb 27 2012 22:10:21 GMT")
    (let ((buf (find-file "/home/test/somefile")))
      (unwind-protect
          (with-current-buffer buf
            (should
             (equal "This is a file."
                    (buffer-substring (point-min) (point-max)))))
        (kill-buffer buf)))
    (should (file-exists-p "/home/test/somefile"))
    (should-not (file-exists-p "/home/test/otherfile"))
    (should-not (file-exists-p "/home/dir/somefile"))
    (should (equal
             (expand-file-name "~/somefile")
             "/home/test/somefile"))
    (should (equal
             '(20299 65357)
             (elt (file-attributes "/home/test/somefile") 5)))))

(provide 'fakir)
;
;;; fakir.el ends here