emacs/test/lisp/net/eww-tests.el

;;; eww-tests.el --- tests for eww.el  -*- lexical-binding: t; -*-

;; Copyright (C) 2024 Free Software Foundation, Inc.

;; This file is part of GNU Emacs.

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;; 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.

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;; but WITHOUT ANY WARRANTY; without even the implied warranty of
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;; You should have received a copy of the GNU General Public License
;; along with GNU Emacs.  If not, see <https://www.gnu.org/licenses/>.

;;; Commentary:

;;; Code:

(require 'ert)
(require 'eww)

(defvar eww-test--response-function (lambda (url) (concat "\n" url))
  "A function for returning a mock response for URL.
The default just returns an empty list of headers URL as the body.")

(defmacro eww-test--with-mock-retrieve (&rest body)
  "Evaluate BODY with a mock implementation of `eww-retrieve'.
This avoids network requests during our tests.  Additionally, prepare a
temporary EWW buffer for our tests."
  (declare (indent 1))
    `(cl-letf (((symbol-function 'eww-retrieve)
                (lambda (url callback args)
                  (with-temp-buffer
                    (insert (funcall eww-test--response-function url))
                    (apply callback nil args)))))
       (with-temp-buffer
         (eww-mode)
         ,@body)))

(defun eww-test--history-urls ()
  (mapcar (lambda (elem) (plist-get elem :url)) eww-history))

;;; Tests:

(ert-deftest eww-test/history/new-page ()
  "Test that when visiting a new page, the previous one goes into the history."
  (eww-test--with-mock-retrieve
    (eww "one.invalid")
    (eww "two.invalid")
    (should (equal (eww-test--history-urls)
                   '("http://one.invalid/")))
    (eww "three.invalid")
    (should (equal (eww-test--history-urls)
                   '("http://two.invalid/"
                     "http://one.invalid/")))))

(ert-deftest eww-test/history/back-forward ()
  "Test that navigating through history just changes our history position.
See bug#69232."
  (eww-test--with-mock-retrieve
    (eww "one.invalid")
    (eww "two.invalid")
    (eww "three.invalid")
    (let ((url-history '("http://three.invalid/"
                         "http://two.invalid/"
                         "http://one.invalid/")))
      ;; Go back one page.  This should add "three.invalid" to the
      ;; history, making our position in the list 2.
      (eww-back-url)
      (should (equal (eww-test--history-urls) url-history))
      (should (= eww-history-position 2))
      ;; Go back again.
      (eww-back-url)
      (should (equal (eww-test--history-urls) url-history))
      (should (= eww-history-position 3))
      ;; At the beginning of the history, so trying to go back should
      ;; signal an error.
      (should-error (eww-back-url))
      ;; Go forward once.
      (eww-forward-url)
      (should (equal (eww-test--history-urls) url-history))
      (should (= eww-history-position 2))
      ;; Go forward again.
      (eww-forward-url)
      (should (equal (eww-test--history-urls) url-history))
      (should (= eww-history-position 1))
      ;; At the end of the history, so trying to go forward should
      ;; signal an error.
      (should-error (eww-forward-url)))))

(ert-deftest eww-test/history/reload-in-place ()
  "Test that reloading historical pages updates their history entry in-place.
See bug#69232."
  (eww-test--with-mock-retrieve
    (eww "one.invalid")
    (eww "two.invalid")
    (eww "three.invalid")
    (eww-back-url)
    ;; Make sure our history has the original page text.
    (should (equal (plist-get (nth 1 eww-history) :text)
                   "http://two.invalid/"))
    (should (= eww-history-position 2))
    ;; Reload the page.
    (let ((eww-test--response-function
           (lambda (url) (concat "\nreloaded " url))))
      (eww-reload)
      (should (= eww-history-position 2)))
    ;; Go to another page, and make sure the history is correct,
    ;; including the reloaded page text.
    (eww "four.invalid")
    (should (equal (eww-test--history-urls) '("http://two.invalid/"
                                              "http://one.invalid/")))
    (should (equal (plist-get (nth 0 eww-history) :text)
                   "reloaded http://two.invalid/"))
    (should (= eww-history-position 0))))

(ert-deftest eww-test/history/before-navigate/delete-future-history ()
  "Test that going to a new page from a historical one deletes future history.
See bug#69232."
  (eww-test--with-mock-retrieve
    (eww "one.invalid")
    (eww "two.invalid")
    (eww "three.invalid")
    (eww-back-url)
    (eww "four.invalid")
    (eww "five.invalid")
    (should (equal (eww-test--history-urls) '("http://four.invalid/"
                                              "http://two.invalid/"
                                              "http://one.invalid/")))
    (should (= eww-history-position 0))))

(ert-deftest eww-test/history/before-navigate/ignore-history ()
  "Test that going to a new page from a historical one preserves history.
This sets `eww-before-browse-history-function' to `ignore' to preserve
history.  See bug#69232."
  (let ((eww-before-browse-history-function #'ignore))
    (eww-test--with-mock-retrieve
      (eww "one.invalid")
      (eww "two.invalid")
      (eww "three.invalid")
      (eww-back-url)
      (eww "four.invalid")
      (eww "five.invalid")
      (should (equal (eww-test--history-urls) '("http://four.invalid/"
                                                "http://three.invalid/"
                                                "http://two.invalid/"
                                                "http://one.invalid/")))
      (should (= eww-history-position 0)))))

(ert-deftest eww-test/history/before-navigate/clone-previous ()
  "Test that going to a new page from a historical one clones prior history.
This sets `eww-before-browse-history-function' to
`eww-clone-previous-history' to clone the history.  See bug#69232."
  (let ((eww-before-browse-history-function #'eww-clone-previous-history))
    (eww-test--with-mock-retrieve
      (eww "one.invalid")
      (eww "two.invalid")
      (eww "three.invalid")
      (eww-back-url)
      (eww "four.invalid")
      (eww "five.invalid")
      (should (equal (eww-test--history-urls)
                     '(;; New page and cloned history.
                       "http://four.invalid/"
                       "http://two.invalid/"
                       "http://one.invalid/"
                       ;; Original history.
                       "http://three.invalid/"
                       "http://two.invalid/"
                       "http://one.invalid/")))
      (should (= eww-history-position 0)))))

(provide 'eww-tests)
;; eww-tests.el ends here