* test/automated/sort-tests.el: New file

Tests in this file are randomly generated and then tested with
regular, reverse, and case-fold sorting.

diff --git a/test/automated/sort-tests.el b/test/automated/sort-tests.el
new file mode 100644 (file)
index 0000000..22acb83
--- /dev/null
+++ b/test/automated/sort-tests.el
@@ -0,0 +1,106 @@
+;;; sort-tests.el --- Tests for sort.el              -*- lexical-binding: t; -*-
+
+;; Copyright (C) 2015 Free Software Foundation, Inc.
+
+;; Author: Artur Malabarba <bruce.connor.am@gmail.com>
+
+;; 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/>.
+
+;;; Code:
+
+(require 'ert)
+(require 'sort)
+
+(defun sort-tests-random-word (n)
+  (mapconcat (lambda (_) (string (let ((c (random 52)))
+                              (+ (if (> c 25) 71 65)
+                                 c))))
+             (make-list n nil) ""))
+
+(defun sort-tests--insert-words-sort-and-compare (words separator function reverse less-predicate)
+  (with-temp-buffer
+    (let ((aux words))
+      (while aux
+        (insert (pop aux))
+        (when aux
+          (insert separator))))
+    ;; Final newline.
+    (insert "\n")
+    (funcall function reverse (point-min) (point-max))
+    (let ((sorted-words
+           (mapconcat #'identity
+                      (let ((x (sort (copy-sequence words) less-predicate)))
+                        (if reverse (reverse x) x))
+                      separator)))
+      (should (string= (substring (buffer-string) 0 -1) sorted-words)))))
+
+;;; This function uses randomly generated tests and should satisfy
+;;; most needs for this lib.
+(cl-defun sort-tests-test-sorter-function (separator function &key generator less-pred noreverse)
+  "Check that FUNCTION correctly sorts words separated by SEPARATOR.
+This checks whether it is equivalent to sorting a list of such
+words via LESS-PREDICATE, and then inserting them separated by
+SEPARATOR.
+LESS-PREDICATE defaults to `string-lessp'.
+GENERATOR is a function called with one argument that returns a
+word, it defaults to `sort-tests-random-word'.
+NOREVERSE means that the first arg of FUNCTION is not used for
+reversing the sort."
+  (dotimes (n 20)
+    ;; Sort n words of length n.
+    (let ((words (mapcar (or generator #'sort-tests-random-word) (make-list n n)))
+          (sort-fold-case nil)
+          (less-pred (or less-pred #'string<)))
+      (sort-tests--insert-words-sort-and-compare words separator function nil less-pred)
+      (unless noreverse
+        (sort-tests--insert-words-sort-and-compare
+         words separator function 'reverse less-pred))
+      (let ((less-pred-case (lambda (a b) (funcall less-pred (downcase a) (downcase b))))
+            (sort-fold-case t))
+        (sort-tests--insert-words-sort-and-compare words separator function nil less-pred-case)
+        (unless noreverse
+          (sort-tests--insert-words-sort-and-compare
+           words separator function 'reverse less-pred-case))))))
+
+(ert-deftest sort-tests--lines ()
+  (sort-tests-test-sorter-function "\n" #'sort-lines))
+
+(ert-deftest sort-tests--paragraphs ()
+  (let ((paragraph-separate "[\s\t\f]*$"))
+    (sort-tests-test-sorter-function "\n\n" #'sort-paragraphs)))
+
+(ert-deftest sort-tests--numeric-fields ()
+  (cl-labels ((field-to-number (f) (string-to-number (car (split-string f)))))
+    (sort-tests-test-sorter-function "\n" (lambda (_ l r) (sort-numeric-fields 1 l (1- r)))
+                           :noreverse t
+                           :generator (lambda (_) (format "%s %s" (random) (sort-tests-random-word 20)))
+                           :less-pred (lambda (a b) (< (field-to-number a)
+                                                  (field-to-number b))))))
+
+(ert-deftest sort-tests--fields-1 ()
+  (cl-labels ((field-n (f n) (elt (split-string f) (1- n))))
+    (sort-tests-test-sorter-function "\n" (lambda (_ l r) (sort-fields 1 l (1- r)))
+                           :noreverse t
+                           :generator (lambda (n) (concat (sort-tests-random-word n) " " (sort-tests-random-word n)))
+                           :less-pred (lambda (a b) (string< (field-n a 1) (field-n b 1))))))
+
+(ert-deftest sort-tests--fields-2 ()
+  (cl-labels ((field-n (f n) (elt (split-string f) (1- n))))
+    (sort-tests-test-sorter-function "\n" (lambda (_ l r) (sort-fields 2 l (1- r)))
+                           :noreverse t
+                           :generator (lambda (n) (concat (sort-tests-random-word n) " " (sort-tests-random-word n)))
+                           :less-pred (lambda (a b) (string< (field-n a 2) (field-n b 2))))))
+
+(provide 'sort-tests)
+;;; sort-tests.el ends here