emacs/lisp/emacs-lisp/ert-font-lock.el
2023-12-10 13:22:04 +01:00

364 lines
12 KiB
EmacsLisp

;;; ert-font-lock.el --- ERT Font Lock -*- lexical-binding: t -*-
;; Copyright (C) 2023 Free Software Foundation, Inc.
;; Author: Vladimir Kazanov
;; Keywords: lisp, tools
;; 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:
;;
;; ERT Font Lock is an extension to the Emacs Lisp Regression Test
;; library (ERT) providing a convenient way to check syntax
;; highlighting provided by font-lock.
;;
;; ert-font-lock entry points are functions
;; `ert-font-lock-test-string' and `ert-font-lock-test-file' and
;; convenience macros: `ert-font-lock-deftest' and
;; `ert-font-lock-deftest-file'.
;;
;; See unit tests in ert-font-lock-tests.el for usage examples.
;;; Code:
(require 'ert)
(require 'newcomment)
(require 'pcase)
(defconst ert-font-lock--assertion-re
(rx
;; column specifiers
(group (or "^" "<-"))
(one-or-more " ")
;; optional negation of the face specification
(group (optional "!"))
;; face symbol name
(group (one-or-more (or alphanumeric "-" "_" "."))))
"An ert-font-lock assertion regex.")
(defun ert-font-lock--validate-major-mode (mode)
"Validate if MODE is a valid major mode."
(unless (functionp mode)
(error "Invalid major mode: %S. Please specify a valid major mode for
syntax highlighting tests" mode)))
(defun ert-font-lock--test-body-str (mode str test-name)
"Run assertions from STR.
Argument MODE - major mode to test.
Argument TEST-NAME - name of the currently running ert test."
(ert-font-lock--validate-major-mode mode)
(with-temp-buffer
(insert str)
(funcall mode)
(font-lock-ensure)
(let ((tests (ert-font-lock--parse-comments)))
(ert-font-lock--check-faces tests)))
test-name)
(defun ert-font-lock--test-body-file (mode file test-name)
"Run assertions from FILE.
Argument MODE - major mode to test.
Argument TEST-NAME - name of the currently running ert test."
(ert-font-lock--validate-major-mode mode)
(ert-font-lock-test-file file mode)
test-name)
(defun ert-font-lock--parse-macro-args (doc-keys-mode-arg)
"Parse DOC-KEYS-MODE-ARG macro argument list."
(let (doc doc-p mode arg)
(when (stringp (car doc-keys-mode-arg))
(setq doc (pop doc-keys-mode-arg)
doc-p t))
(pcase-let
((`(,keys ,mode-arg)
(ert--parse-keys-and-body doc-keys-mode-arg)))
(unless (symbolp (car mode-arg))
(error "A major mode symbol expected: %S" (car mode-arg)))
(setq mode (pop mode-arg))
(unless (stringp (car mode-arg))
(error "A string or file with assertions expected: %S" (car mode-arg)))
(setq arg (pop mode-arg))
(list doc doc-p keys mode arg))))
;;;###autoload
(defmacro ert-font-lock-deftest (name &rest docstring-keys-mode-and-str)
"Define test NAME (a symbol) using assertions from TEST-STR.
Other than MAJOR-MODE and TEST-STR parameters, this macro accepts
the same parameters and keywords as `ert-deftest' and is intended
to be used through `ert'.
\(fn NAME () [DOCSTRING] [:expected-result RESULT-TYPE] \
[:tags \\='(TAG...)] MAJOR-MODE TEST-STR)"
(declare (debug (&define [&name "test@" symbolp]
sexp [&optional stringp]
[&rest keywordp sexp]
symbolp
stringp))
(doc-string 3)
(indent 2))
(pcase-let ((`(,documentation
,documentation-supplied-p
,keys ,mode ,arg)
(ert-font-lock--parse-macro-args docstring-keys-mode-and-str)))
`(ert-set-test ',name
(make-ert-test
:name ',name
,@(when documentation-supplied-p
`(:documentation ,documentation))
,@(when (map-contains-key keys :expected-result)
`(:expected-result-type ,(map-elt keys :expected-result)))
,@(when (map-contains-key keys :tags)
`(:tags ,(map-elt keys :tags)))
:body (lambda () (ert-font-lock--test-body-str ',mode ,arg ',name))
:file-name ,(or (macroexp-file-name) buffer-file-name)))))
;;;###autoload
(defmacro ert-font-lock-deftest-file (name &rest docstring-keys-mode-and-file)
"Define test NAME (a symbol) using assertions from FILE.
FILE - path to a file with assertions in ERT resource director as
return by `ert-resource-directory'.
Other than MAJOR-MODE and FILE parameters, this macro accepts the
same parameters and keywords as `ert-deftest' and is intended to
be used through `ert'.
\(fn NAME () [DOCSTRING] [:expected-result RESULT-TYPE] \
[:tags \\='(TAG...)] MAJOR-MODE FILE)"
(declare (debug (&define [&name "test@" symbolp]
sexp [&optional stringp]
[&rest keywordp sexp]
symbolp
stringp))
(doc-string 3)
(indent 2))
(pcase-let ((`(,documentation
,documentation-supplied-p
,keys ,mode ,arg)
(ert-font-lock--parse-macro-args docstring-keys-mode-and-file)))
`(ert-set-test ',name
(make-ert-test
:name ',name
,@(when documentation-supplied-p
`(:documentation ,documentation))
,@(when (map-contains-key keys :expected-result)
`(:expected-result-type ,(map-elt keys :expected-result)))
,@(when (map-contains-key keys :tags)
`(:tags ,(map-elt keys :tags)))
:body (lambda () (ert-font-lock--test-body-file
',mode (ert-resource-file ,arg) ',name))
:file-name ,(or (macroexp-file-name) buffer-file-name)))))
(defun ert-font-lock--in-comment-p ()
"Check if the current point is inside a comment."
(nth 4 (syntax-ppss)))
(defun ert-font-lock--comment-start-p ()
"Check if the current point starts a comment."
(or
;; regexps use syntax tables so let's check that first
(looking-at "\\s<")
;; check newcomment.el facilities
(and comment-start (looking-at (regexp-quote comment-start)))
(and comment-start-skip (looking-at comment-start-skip))
;; sometimes comment syntax is just hardcoded
(and (derived-mode-p '(c-mode c++-mode java-mode))
(looking-at-p "//"))))
(defun ert-font-lock--line-comment-p ()
"Return t if the current line is a comment-only line."
(syntax-ppss)
(save-excursion
(beginning-of-line)
(skip-syntax-forward " ")
;; skip empty lines
(unless (eolp)
(or
;; multiline comments
(ert-font-lock--in-comment-p)
;; single line comments
(ert-font-lock--comment-start-p)))))
(defun ert-font-lock--line-assertion-p ()
"Return t if the current line contains an assertion."
(syntax-ppss)
(save-excursion
(beginning-of-line)
(skip-syntax-forward " ")
(re-search-forward ert-font-lock--assertion-re
(line-end-position) t 1)))
(defun ert-font-lock--goto-first-char ()
"Move the point to the first character."
(beginning-of-line)
(skip-syntax-forward " "))
(defun ert-font-lock--get-first-char-column ()
"Get the position of the first non-empty char in the current line."
(save-excursion
(ert-font-lock--goto-first-char)
(- (point) (line-beginning-position))))
(defun ert-font-lock--parse-comments ()
"Read test assertions from comments in the current buffer."
(let ((tests '())
(curline 1)
(linetocheck -1))
(goto-char (point-min))
;; Go through all lines, for comments check if there are
;; assertions. For non-comment and comment/non-assert lines
;; remember the last line seen.
(while (not (eobp))
(catch 'nextline
;; Not a comment? remember the line, move to the next one
(unless (ert-font-lock--line-comment-p)
(setq linetocheck curline)
(throw 'nextline t))
;; A comment. Not an assertion? remember the line to be
;; checked, move to the next line
(unless (ert-font-lock--line-assertion-p)
(setq linetocheck curline)
(throw 'nextline t))
;; Collect the assertion
(when (re-search-forward ert-font-lock--assertion-re
(line-end-position) t 1)
(unless (> linetocheck -1)
(user-error "Invalid test comment syntax at line %d. Expected a line to test before the comment line" curline))
;; construct a test
(let* (;; either comment start char column (for arrows) or
;; caret column
(column-checked (if (equal (match-string-no-properties 1) "^")
(- (match-beginning 1) (line-beginning-position))
(ert-font-lock--get-first-char-column)))
;; negate the face?
(negation (string-equal (match-string-no-properties 2) "!"))
;; the face that is supposed to be in the position specified
(face (match-string-no-properties 3)))
(push (list :line-checked linetocheck
:line-assert curline
:column-checked column-checked
:face face
:negation negation)
tests))))
;; next line
(setq curline (1+ curline))
(forward-line 1))
(reverse tests)))
(defun ert-font-lock--point-at-line-and-column (line column)
"Get the buffer position for LINE and COLUMN."
(save-excursion
(goto-char (point-min))
(forward-line (1- line))
(move-to-column column)
(point)))
(defun ert-font-lock--get-line (line-number)
"Return the content of the line specified by LINE-NUMBER."
(save-excursion
(goto-char (point-min))
(forward-line (1- line-number))
(buffer-substring-no-properties (line-beginning-position) (line-end-position))))
(defun ert-font-lock--check-faces (tests)
"Check if the current buffer is fontified correctly.
TESTS - tests to run.
The function is meant to be run from within an ERT test."
(dolist (test tests)
(let* ((line-checked (plist-get test :line-checked))
(line-assert (plist-get test :line-assert))
(column-checked (plist-get test :column-checked))
(expected-face (intern (plist-get test :face)))
(negation (plist-get test :negation))
(actual-face (get-text-property (ert-font-lock--point-at-line-and-column line-checked column-checked) 'face))
(line-str (ert-font-lock--get-line line-checked))
(line-assert-str (ert-font-lock--get-line line-assert)))
(when (not (eq actual-face expected-face))
(ert-fail
(list (format "Expected face %S, got %S on line %d column %d"
expected-face actual-face line-checked column-checked)
:line line-str
:assert line-assert-str)))
(when (and negation (eq actual-face expected-face))
(ert-fail
(list (format "Did not expect face %S face on line %d, column %d"
actual-face line-checked column-checked)
:line line-str
:assert line-assert-str))))))
;;;###autoload
(defun ert-font-lock-test-string (test-string mode)
"Check font faces in TEST-STRING set by MODE.
The function is meant to be run from within an ERT test."
(ert-font-lock--validate-major-mode mode)
(with-temp-buffer
(insert test-string)
(funcall mode)
(font-lock-ensure)
(ert-font-lock--check-faces (ert-font-lock--parse-comments)))
(ert-pass))
;;;###autoload
(defun ert-font-lock-test-file (filename mode)
"Check font faces in FILENAME set by MODE.
The function is meant to be run from within an ERT test."
(ert-font-lock--validate-major-mode mode)
(with-temp-buffer
(insert-file-contents filename)
(funcall mode)
(font-lock-ensure)
(ert-font-lock--check-faces (ert-font-lock--parse-comments)))
(ert-pass))
(provide 'ert-font-lock)
;;; ert-font-lock.el ends here