Load mm-util as needed for url-file and url-data (Bug#30258)

* lisp/url/url-file.el (url-file):
* lisp/url/url-misc.el (url-data): Require `mm-util' before calling
`mm-disable-multibyte'.
* test/lisp/url/url-file-resources/file.txt:
* test/lisp/url/url-file-tests.el:
* test/lisp/url/url-misc-tests.el: New tests.

lisp/url/url-file.el

@@ -188,6 +188,7 @@ to them."
 	(url-find-file-dired filename)
       (with-current-buffer
 	  (setq buffer (generate-new-buffer " *url-file*"))
+        (require 'mm-util)
 	(mm-disable-multibyte)
 	(setq url-current-object url)
 	(insert "Content-type: " (or content-type "application/octet-stream") "\n")

lisp/url/url-misc.el

@@ -99,6 +99,7 @@
 		(eq ?\; (aref mediatype 0)))
 	  (setq mediatype (concat "text/plain" mediatype))))
       (set-buffer (generate-new-buffer " *url-data*"))
+      (require 'mm-util)
       (mm-disable-multibyte)
       (insert (format "Content-Length: %d\n" (length data))
 	      "Content-Type: " mediatype "\n"

test/lisp/url/url-file-resources/file.txt

@@ -0,0 +1 @@
+Some file data

test/lisp/url/url-file-tests.el

@@ -0,0 +1,50 @@
+;;; url-file-tests.el --- Test suite for url-file. -*- lexical-binding: t -*-
+
+;; Copyright (C) 2018 Free Software Foundation, Inc.
+
+;; This file is part of GNU Emacs.
+
+;; GNU Emacs 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.
+
+;; GNU Emacs 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 GNU Emacs.  If not, see <https://www.gnu.org/licenses/>.
+
+;;; Commentary:
+
+;;; Code:
+
+(require 'url-file)
+(require 'ert)
+
+(defconst url-file-tests-data-directory
+  (expand-file-name "lisp/url/url-file-resources"
+                    (or (getenv "EMACS_TEST_DIRECTORY")
+                        (expand-file-name "../../.."
+                                          (or load-file-name
+                                              buffer-file-name))))
+  "Directory for url-file test files.")
+
+(ert-deftest url-file ()
+  "Test reading file via file:// URL."
+  (let ((file (expand-file-name "file.txt" url-file-tests-data-directory)))
+    (should (equal
+             (with-current-buffer
+                 (url-file (url-generic-parse-url (concat "file://" file))
+                           #'ignore nil)
+               (prog1 (buffer-substring (point) (point-max))
+                 (kill-buffer)))
+             (with-temp-buffer
+               (insert-file-contents-literally file)
+               (buffer-string))))))
+
+(provide 'url-file-tests)
+
+;;; url-file-tests.el ends here

test/lisp/url/url-misc-tests.el

@@ -0,0 +1,41 @@
+;;; url-misc-tests.el --- Test suite for url-misc. -*- lexical-binding: t -*-
+
+;; Copyright (C) 2018 Free Software Foundation, Inc.
+
+;; This file is part of GNU Emacs.
+
+;; GNU Emacs 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.
+
+;; GNU Emacs 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 GNU Emacs.  If not, see <https://www.gnu.org/licenses/>.
+
+;;; Commentary:
+
+;;; Code:
+
+(require 'url-misc)
+(require 'ert)
+
+(ert-deftest url-misc-data ()
+  "Test reading data: URL."
+  (should (equal
+           (with-current-buffer
+               (url-data (url-generic-parse-url "data:;,some%20text"))
+             (goto-char (point-min))
+             (forward-paragraph)
+             (forward-line)
+             (prog1 (buffer-substring (point) (point-max))
+               (kill-buffer)))
+           "some text")))
+
+(provide 'url-misc-tests)
+
+;;; url-misc-tests.el ends here