Support completion of attribute values in CSS mode

* lisp/textmodes/css-mode.el (css-property-alist): New defconst
holding CSS identifiers and the values they can have.
(css-property-ids): Compute dynamically from `css-property-alist'.
(css-value-class-alist): New defconst holding property value classes
and their values.
(css--property-value-cache): New variable providing a cache for
`css--property-values'.
(css--value-class-lookup): New function for computing a list of values
in a value class.
(css--property-values): New function for computing a list of possible
values for a CSS property.
(css--complete-property-value): New function for completing a property
value.
(css-completion-at-point): Add support for completing property values.
* test/lisp/textmodes/css-mode-tests.el: New file.

1 files changed, 66 insertions, 0 deletions

diff --git a/test/lisp/textmodes/css-mode-tests.el b/test/lisp/textmodes/css-mode-tests.el
new file mode 100644
index 0000000000..9c5953db4a
--- /dev/null
+++ b/test/lisp/textmodes/css-mode-tests.el
@@ -0,0 +1,66 @@
+;;; css-mode-tests.el --- Test suite for CSS mode  -*- lexical-binding: t; -*-
+
+;; Copyright (C) 2016 Free Software Foundation, Inc.
+
+;; Author: Simen Heggestøyl <simenheg@gmail.com>
+;; Keywords: internal
+
+;; This file is 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:
+
+;;; Code:
+
+(require 'ert)
+(require 'css-mode)
+
+(ert-deftest css-test-property-values ()
+  ;; The `float' property has a flat value list.
+  (should
+   (equal (sort (css--property-values "float") #'string-lessp)
+          '("left" "none" "right")))
+
+  ;; The `list-style' property refers to several other properties.
+  (should
+   (equal (sort (css--property-values "list-style") #'string-lessp)
+          (sort (append (css--property-values "list-style-type")
+                        (css--property-values "list-style-position")
+                        (css--property-values "list-style-image"))
+                #'string-lessp)))
+
+  ;; The `position' property is tricky because it's also the name of a
+  ;; value class.
+  (should
+   (equal (sort (css--property-values "position") #'string-lessp)
+          '("absolute" "fixed" "relative" "static")))
+
+  ;; The `background-position' property should refer to the `position'
+  ;; value class, not the property of the same name.
+  (should
+   (equal (css--property-values "background-position")
+          (css--value-class-lookup 'position)))
+
+  ;; Check that the `color' property doesn't cause infinite recursion
+  ;; because it refers to the value class of the same name.
+  (should (= (length (css--property-values "color")) 18)))
+
+(ert-deftest css-test-value-class-lookup ()
+  (should
+   (equal (sort (css--value-class-lookup 'position) #'string-lessp)
+          '("bottom" "center" "left" "right" "top"))))
+
+(provide 'css-mode-tests)
+;;; css-mode-tests.el ends here