Add completion of `calc()' in CSS mode

* lisp/textmodes/css-mode.el (css-value-class-alist): Add `calc()' as
a completion candidate for several value classes.
(css--value-class-lookup): Return only unique results.

* test/lisp/textmodes/css-mode-tests.el
(css-test-property-values-no-duplicates)
(css-test-value-class-lookup): Update to reflect the above changes.

1 files changed, 2 insertions, 2 deletions

diff --git a/test/lisp/textmodes/css-mode-tests.el b/test/lisp/textmodes/css-mode-tests.el
index 5d5873b301b..4c0a3572b36 100644
--- a/test/lisp/textmodes/css-mode-tests.el
+++ b/test/lisp/textmodes/css-mode-tests.el
@@ -72,12 +72,12 @@
   ;; removed, it'll contain at least two instances of `auto'.
   (should
    (equal (sort (css--property-values "flex") #'string-lessp)
-          '("auto" "content" "none"))))
+          '("auto" "calc()" "content" "none"))))
 
 (ert-deftest css-test-value-class-lookup ()
   (should
    (equal (sort (css--value-class-lookup 'position) #'string-lessp)
-          '("bottom" "center" "left" "right" "top"))))
+          '("bottom" "calc()" "center" "left" "right" "top"))))
 
 (provide 'css-mode-tests)
 ;;; css-mode-tests.el ends here