* test/lisp/progmodes/project-tests.el (project-tests--trivial)
(project-root, project-ignores): New test project type.
(project-ignores): New unit test.
This is a useful abstraction, and saves a few levels of indentation in
the test body.
* test/lisp/progmodes/project-tests.el
(project-tests--with-temporary-directory): New helper macro.
(project/quoted-directory): Use it.
This is only a band-aid; it would be better to fix xref.el to work
with quoted filenames as well.
* lisp/progmodes/project.el (project--find-regexp-in-files): Unquote
filenames before passing them to 'xref-matches-in-files'.
* test/lisp/progmodes/project-tests.el (project/quoted-directory):
Also test 'project-find-regexp'.
* test/lisp/progmodes/project-tests.el (project/quoted-directory):
Skip if the 'find' program isn't available. The 'project-files'
function uses 'find' to obtain the list of project files.
* lisp/progmodes/project.el (project--files-in-directory): Unquote
directory name before passing it to 'find'.
(project--remote-file-names): Requote local filenames if the original
directory is quoted.
* test/lisp/progmodes/project-tests.el (project/quoted-directory): New
unit test.
