;;; seq-tests.el --- Tests for seq.el  -*- lexical-binding:t -*-

;; Copyright (C) 2014-2024 Free Software Foundation, Inc.

;; Author: Nicolas Petton <nicolas@petton.fr>
;; Maintainer: emacs-devel@gnu.org

;; 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:

;; Tests for sequences.el

;;; Code:

(require 'ert)
(require 'seq)

(eval-when-compile
  (require 'cl-lib))

(defmacro with-test-sequences (spec &rest body)
  "Successively bind VAR to a list, vector, and string built from SEQ.
Evaluate BODY for each created sequence.

\(fn (var seq) body)"
  (declare (indent 1) (debug ((symbolp form) body)))
  (let ((initial-seq (make-symbol "initial-seq")))
    `(let ((,initial-seq ,(cadr spec)))
       ,@(mapcar (lambda (s)
                   `(let ((,(car spec) (apply (function ,s) ,initial-seq)))
                      ,@body))
                 '(list vector string)))))

(defun same-contents-p (seq1 seq2)
  "Return t if SEQ1 and SEQ2 have the same contents, nil otherwise."
  (equal (append seq1 '()) (append seq2 '())))

(defun test-sequences-evenp (integer)
  "Return t if INTEGER is even."
  (eq (logand integer 1) 0))

(defun test-sequences-oddp (integer)
  "Return t if INTEGER is odd."
  (not (test-sequences-evenp integer)))

(ert-deftest test-setf-seq-elt ()
  (with-test-sequences (seq '(1 2 3))
    (setf (seq-elt seq 1) 4)
    (should (= 4 (seq-elt seq 1)))))

(ert-deftest test-seq-drop ()
  (with-test-sequences (seq '(1 2 3 4))
    (should (equal (seq-drop seq 0) seq))
    (should (equal (seq-drop seq 1) (seq-subseq seq 1)))
    (should (equal (seq-drop seq 2) (seq-subseq seq 2)))
    (should (seq-empty-p (seq-drop seq 4)))
    (should (seq-empty-p (seq-drop seq 10))))
  (with-test-sequences (seq '())
    (should (seq-empty-p (seq-drop seq 0)))
    (should (seq-empty-p (seq-drop seq 1)))))

(ert-deftest test-seq-take ()
  (with-test-sequences (seq '(2 3 4 5))
    (should (seq-empty-p (seq-take seq 0)))
    (should (= (seq-length (seq-take seq 1)) 1))
    (should (= (seq-elt (seq-take seq 1) 0) 2))
    (should (same-contents-p (seq-take seq 3) '(2 3 4)))
    (should (equal (seq-take seq 10) seq))))

(ert-deftest test-seq-drop-while ()
  (with-test-sequences (seq '(1 3 2 4))
    (should (equal (seq-drop-while #'test-sequences-oddp seq)
                   (seq-drop seq 2)))
    (should (equal (seq-drop-while #'test-sequences-evenp seq)
                   seq))
    (should (seq-empty-p (seq-drop-while #'numberp seq))))
  (with-test-sequences (seq '())
    (should (seq-empty-p (seq-drop-while #'test-sequences-oddp seq)))))

(ert-deftest test-seq-take-while ()
  (with-test-sequences (seq '(1 3 2 4))
    (should (equal (seq-take-while #'test-sequences-oddp seq)
                   (seq-take seq 2)))
    (should (seq-empty-p (seq-take-while #'test-sequences-evenp seq)))
    (should (equal (seq-take-while #'numberp seq) seq)))
  (with-test-sequences (seq '())
    (should (seq-empty-p (seq-take-while #'test-sequences-oddp seq)))))

(ert-deftest test-seq-map-indexed ()
  (should (equal (seq-map-indexed (lambda (elt i)
                                    (list elt i))
                                  nil)
                 nil))
  (should (equal (seq-map-indexed (lambda (elt i)
                                    (list elt i))
                                  '(a b c d))
                 '((a 0) (b 1) (c 2) (d 3)))))

(ert-deftest test-seq-do-indexed ()
  (let (result)
    (seq-do-indexed (lambda (elt i) (push (list elt i) result)) ())
    (should-not result))
  (with-test-sequences (seq '(4 5 6))
    (let (result)
      (seq-do-indexed (lambda (elt i) (push (list elt i) result)) seq)
      (should (equal (seq-elt result 0) '(6 2)))
      (should (equal (seq-elt result 1) '(5 1)))
      (should (equal (seq-elt result 2) '(4 0))))))

(ert-deftest test-seq-filter ()
  (with-test-sequences (seq '(6 7 8 9 10))
    (should (equal (seq-filter #'test-sequences-evenp seq) '(6 8 10)))
    (should (equal (seq-filter #'test-sequences-oddp seq) '(7 9)))
    (should (equal (seq-filter (lambda (_) nil) seq) '())))
  (with-test-sequences (seq '())
    (should (equal (seq-filter #'test-sequences-evenp seq) '()))))

(ert-deftest test-seq-remove ()
  (with-test-sequences (seq '(6 7 8 9 10))
    (should (equal (seq-remove #'test-sequences-evenp seq) '(7 9)))
    (should (equal (seq-remove #'test-sequences-oddp seq) '(6 8 10)))
    (should (same-contents-p (seq-remove (lambda (_) nil) seq) seq)))
  (with-test-sequences (seq '())
    (should (equal (seq-remove #'test-sequences-evenp seq) '()))))

(ert-deftest test-seq-remove-at-position ()
  (with-test-sequences (seq '(1 2 3 4))
    (should (same-contents-p (seq-remove-at-position seq 2) '(1 2 4)))
    (should (same-contents-p (seq-remove-at-position seq 0) '(2 3 4)))
    (should (same-contents-p (seq-remove-at-position seq 3) '(1 2 3)))
    (should (eq (type-of (seq-remove-at-position seq 2))
                (type-of seq)))))

(ert-deftest test-seq-count ()
  (with-test-sequences (seq '(6 7 8 9 10))
    (should (equal (seq-count #'test-sequences-evenp seq) 3))
    (should (equal (seq-count #'test-sequences-oddp seq) 2))
    (should (equal (seq-count (lambda (_) nil) seq) 0)))
  (with-test-sequences (seq '())
    (should (equal (seq-count #'test-sequences-evenp seq) 0))))

(ert-deftest test-seq-reduce ()
  (with-test-sequences (seq '(1 2 3 4))
    (should (= (seq-reduce #'+ seq 0) 10))
    (should (= (seq-reduce #'+ seq 5) 15)))
  (with-test-sequences (seq '())
    (should (eq (seq-reduce #'+ seq 0) 0))
    (should (eq (seq-reduce #'+ seq 7) 7))))

(ert-deftest test-seq-some ()
  (with-test-sequences (seq '(4 3 2 1))
    (should (seq-some #'test-sequences-evenp seq))
    (should (seq-some #'test-sequences-oddp seq))
    (should-not (seq-some (lambda (elt) (> elt 10)) seq)))
  (with-test-sequences (seq '())
    (should-not (seq-some #'test-sequences-oddp seq)))
  (should (seq-some #'null '(1 nil 2))))

(ert-deftest test-seq-find ()
  (with-test-sequences (seq '(4 3 2 1))
    (should (= 4 (seq-find #'test-sequences-evenp seq)))
    (should (= 3 (seq-find #'test-sequences-oddp seq)))
    (should-not (seq-find (lambda (elt) (> elt 10)) seq)))
  (should-not (seq-find #'null '(1 nil 2)))
  (should-not (seq-find #'null '(1 nil 2) t))
  (should-not (seq-find #'null '(1 2 3)))
  (should (seq-find #'null '(1 2 3) 'sentinel)))

(ert-deftest test-seq-contains ()
  (with-suppressed-warnings ((obsolete seq-contains))
    (with-test-sequences (seq '(3 4 5 6))
      (should (seq-contains seq 3))
      (should-not (seq-contains seq 7)))
    (with-test-sequences (seq '())
      (should-not (seq-contains seq 3))
      (should-not (seq-contains seq nil)))))

(ert-deftest test-seq-contains-should-return-the-elt ()
  (with-suppressed-warnings ((obsolete seq-contains))
    (with-test-sequences (seq '(3 4 5 6))
      (should (= 5 (seq-contains seq 5))))))

(ert-deftest test-seq-contains-p ()
  (with-test-sequences (seq '(3 4 5 6))
    (should (eq (seq-contains-p seq 3) t))
    (should-not (seq-contains-p seq 7)))
  (with-test-sequences (seq '())
    (should-not (seq-contains-p seq 3))
    (should-not (seq-contains-p seq nil))))

(ert-deftest test-seq-contains-p-with-nil ()
  (should (seq-contains-p  [nil] nil))
  (should (seq-contains-p '(nil) nil)))

(ert-deftest test-seq-every-p ()
  (with-test-sequences (seq '(43 54 22 1))
    (should (seq-every-p (lambda (_) t) seq))
    (should-not (seq-every-p #'test-sequences-oddp seq))
    (should-not (seq-every-p #'test-sequences-evenp seq)))
  (with-test-sequences (seq '(42 54 22 2))
    (should (seq-every-p #'test-sequences-evenp seq))
    (should-not (seq-every-p #'test-sequences-oddp seq)))
  (with-test-sequences (seq '())
    (should (seq-every-p #'identity seq))
    (should (seq-every-p #'test-sequences-evenp seq))))

(ert-deftest test-seq-set-equal-p ()
  (with-test-sequences (seq1 '(1 2 3))
    (should (seq-set-equal-p seq1 seq1))
    (should (seq-set-equal-p seq1 seq1 #'eq))

    (with-test-sequences (seq2 '(3 2 1))
      (should (seq-set-equal-p seq1 seq2))
      (should (seq-set-equal-p seq2 seq1))
      (should (seq-set-equal-p seq1 seq2 #'eq))
      (should (seq-set-equal-p seq2 seq1 #'eq)))

    (with-test-sequences (seq2 '(3 1))
      (should-not (seq-set-equal-p seq1 seq2))
      (should-not (seq-set-equal-p seq2 seq1))))

  (should (seq-set-equal-p '("a" "b" "c")
                           '("c" "b" "a")))
  (should-not (seq-set-equal-p '("a" "b" "c")
                               '("c" "b" "a") #'eq))
  (should-not (seq-set-equal-p '(("a" 1) ("b" 1) ("c" 1))
                               '(("c" 2) ("b" 2) ("a" 2))))
  (should (seq-set-equal-p '(("a" 1) ("b" 1) ("c" 1))
                           '(("c" 2) ("b" 2) ("a" 2))
                           (lambda (i1 i2) (equal (car i1) (car i2))))))

(ert-deftest test-seq-empty-p ()
  (with-test-sequences (seq '(0))
    (should-not (seq-empty-p seq)))
  (with-test-sequences (seq '(0 1 2))
    (should-not (seq-empty-p seq)))
  (with-test-sequences (seq '())
    (should (seq-empty-p seq))))

(ert-deftest test-seq-sort ()
  (should (equal (seq-sort #'< "cbaf") "abcf"))
  (should (equal (seq-sort #'< '(2 1 9 4)) '(1 2 4 9)))
  (should (equal (seq-sort #'< [2 1 9 4]) [1 2 4 9]))
  (should (equal (seq-sort #'< "") "")))

(ert-deftest test-seq-uniq ()
  (with-test-sequences (seq '(2 4 6 8 6 4 3))
    (should (equal (seq-uniq seq) '(2 4 6 8 3))))
  (with-test-sequences (seq '(3 3 3 3 3))
    (should (equal (seq-uniq seq) '(3))))
  (with-test-sequences (seq '())
    (should (equal (seq-uniq seq) '()))))

(defun seq-tests--list-subseq-ref (list start &optional end)
  "Reference implementation of `seq-subseq' for lists."
  (let ((len (length list)))
    (when (< start 0)
      (setq start (+ start len)))
    (unless end
      (setq end len))
    (when (< end 0)
      (setq end (+ end len)))
    (if (<= 0 start end len)
        (take (- end start) (nthcdr start list))
      (error "bad args"))))

(ert-deftest test-seq-subseq ()
  (with-test-sequences (seq '(2 3 4 5))
    (should (equal (seq-subseq seq 0 4) seq))
    (should (same-contents-p (seq-subseq seq 2 4) '(4 5)))
    (should (same-contents-p (seq-subseq seq 1 3) '(3 4)))
    (should (same-contents-p (seq-subseq seq 1 -1) '(3 4))))
  (should (vectorp (seq-subseq [2 3 4 5] 2)))
  (should (stringp (seq-subseq "foo" 2 3)))
  (should (listp (seq-subseq '(2 3 4 4) 2 3)))
  (should-error (seq-subseq '(1 2 3) 4))
  (should-not   (seq-subseq '(1 2 3) 3))
  (should       (seq-subseq '(1 2 3) -3))
  (should-error (seq-subseq '(1 2 3) 1 4))
  (should       (seq-subseq '(1 2 3) 1 3))
  (should-error (seq-subseq '() -1))
  (should-error (seq-subseq [] -1))
  (should-error (seq-subseq "" -1))
  (should-not (seq-subseq '() 0))
  (should-error (seq-subseq '() 0 -1))

  (dolist (list '(() (a b c d)))
    (ert-info ((prin1-to-string list) :prefix "list: ")
      (let ((len (length list)))
        (dolist (start (number-sequence (- -2 len) (+ 2 len)))
          (ert-info ((prin1-to-string start) :prefix "start: ")
            (dolist (end (cons nil (number-sequence (- -2 len) (+ 2 len))))
              (ert-info ((prin1-to-string end) :prefix "end: ")
                (condition-case res
                    (seq-tests--list-subseq-ref list start end)
                  (error
                   (should-error (seq-subseq list start end)))
                  (:success
                   (should (equal (seq-subseq list start end) res))))))))))))

(cl-defmacro test-setf-seq-subseq-combinations
    (&key init-vals sub-vals result range error)
  "Make a test for each combination of sequence type for `seq-subseq' using `setf'.

- INIT-VALS is a list holding the initial elements.
- RESULT is what the final value should be after substitution.
- ERROR is whether the form should signal `args-out-of-range'.
- SUB-VALS is a list holding the elements to be substituted in.
- RANGE is a list of the `start' and `end' arguments of `seq-subseq'."
  (let ((tests))
    (dolist (type1 '(list vector string))
      (dolist (type2 '(list vector string))
        (push  (if error
                   `(should-error (let ((seq (,type1 ,@init-vals)))
                                    (setf (seq-subseq seq ,@range)
                                          (,type2 ,@sub-vals))
                                    seq)
                                  :type (quote args-out-of-range))
                 `(should (equal (,type1 ,@result)
                                 (let ((seq (,type1 ,@init-vals)))
                                   (setf (seq-subseq seq ,@range)
                                         (,type2 ,@sub-vals))
                                   seq))))
               tests)))
    `(progn ,@tests)))

(ert-deftest test-setf-seq-subseq ()
  "Test using `seq-subseq' with `setf'.

Any combination of sequences should work.

An error should be signalled if the inclusive starting index or
the exclusive ending index is out of the range from 0 through the
length of the sequence, or if the starting index is greater than
the ending index.  If the starting index is equal to the ending
index, then nothing is changed.  If the starting index is equal
to the length of the sequence, then nothing is changed.  It
should signal an error in all the cases that `seq-subseq' signals
an error."
  (test-setf-seq-subseq-combinations
   :init-vals (0 1 2)
   :sub-vals (10 11 12)
   :range (0)
   :result (10 11 12))

  (test-setf-seq-subseq-combinations
   :init-vals (0 1)
   :sub-vals (10 11 12)
   :range (0)
   :result (10 11))

  (test-setf-seq-subseq-combinations
   :init-vals (0 1 2)
   :sub-vals (10 11 12)
   :range (1)
   :result (0 10 11))

  (test-setf-seq-subseq-combinations
   :init-vals (0 1 2)
   :sub-vals (10 11 12)
   :range (1 3)
   :result (0 10 11))

  (test-setf-seq-subseq-combinations
   :init-vals (0 1 2)
   :sub-vals (10 11 12)
   :range (3 1)
   :error t)

  (test-setf-seq-subseq-combinations
   :init-vals (0 1 2)
   :sub-vals (10 11 12)
   :range (1 100)
   :error t)

  (test-setf-seq-subseq-combinations
   :init-vals (0 1 2)
   :sub-vals (10 11 12)
   :range (7)
   :error t)

  (test-setf-seq-subseq-combinations
   :init-vals (0 1 2 3 4)
   :sub-vals (12 13 14 15)
   :range (2 3)
   :result (0 1 12 3 4))

  (test-setf-seq-subseq-combinations
   :init-vals (0 1 2 3 4)
   :sub-vals (12 13 14 15)
   :range (2 2)
   :result (0 1 2 3 4))

  (test-setf-seq-subseq-combinations
   :init-vals (0 1 2 3 4)
   :sub-vals (12 13 14 15)
   :range (5)
   :result (0 1 2 3 4))

  (test-setf-seq-subseq-combinations
   :init-vals (0 1 2 3 4)
   :sub-vals (12 13 14 15)
   :range (6)
   :error t)

  (test-setf-seq-subseq-combinations
   :init-vals (0 1 2 3 4)
   :sub-vals (12 13 14 15)
   :range (5 6)
   :error t)

  (test-setf-seq-subseq-combinations
   :init-vals (0 1 2 3 4 5 6 7 8 9)
   :sub-vals (10 11 12 13 14)
   :range (-2)
   :result (0 1 2 3 4 5 6 7 10 11))

  (test-setf-seq-subseq-combinations
   :init-vals (0 1 2 3 4 5 6 7 8 9)
   :sub-vals (10 11 12 13 14)
   :range (-6 -3)
   :result (0 1 2 3 10 11 12 7 8 9))

  (test-setf-seq-subseq-combinations
   :init-vals (0 1 2 3 4 5 6 7 8 9)
   :sub-vals (10 11 12 13 14)
   :range (-6 -10)
   :error t)

  ;; This range might make sense, but since it would signal an error
  ;; in `seq-subseq', we also signal an error in the `setf' feature.
  (test-setf-seq-subseq-combinations
   :init-vals (0 1 2 3 4 5 6 7 8 9)
   :sub-vals (10 11 12 13 14)
   :range (-6 0)
   :error t)

  (test-setf-seq-subseq-combinations
   :init-vals (0 1 2 3 4 5 6 7 8 9)
   :sub-vals (10 11 12 13 14)
   :range (100)
   :error t)

  (test-setf-seq-subseq-combinations
   :init-vals (0 1 2 3 4 5 6 7 8 9)
   :sub-vals (10 11 12 13 14)
   :range (-100)
   :error t))

(ert-deftest test-seq-concatenate ()
  (with-test-sequences (seq '(2 4 6))
    (should (equal (seq-concatenate 'string seq [8]) (string 2 4 6 8)))
    (should (equal (seq-concatenate 'list seq '(8 10)) '(2 4 6 8 10)))
    (should (equal (seq-concatenate 'vector seq '(8 10)) [2 4 6 8 10]))
    (should (equal (seq-concatenate 'vector nil '(8 10)) [8 10]))
    (should (equal (seq-concatenate 'vector seq nil) [2 4 6]))))

(ert-deftest test-seq-mapcat ()
  (should (equal (seq-mapcat #'seq-reverse '((3 2 1) (6 5 4)))
                 '(1 2 3 4 5 6)))
  (should (equal (seq-mapcat #'seq-reverse '[(3 2 1) (6 5 4)])
                 '(1 2 3 4 5 6)))
  (should (equal (seq-mapcat #'seq-reverse '((3 2 1) (6 5 4)) 'vector)
                 '[1 2 3 4 5 6])))

(ert-deftest test-seq-partition ()
  (should (same-contents-p (seq-partition '(0 1 2 3 4 5 6 7) 3)
                           '((0 1 2) (3 4 5) (6 7))))
  (should (same-contents-p (seq-partition '[0 1 2 3 4 5 6 7] 3)
                           '([0 1 2] [3 4 5] [6 7])))
  (should (same-contents-p (seq-partition "Hello world" 2)
                           '("He" "ll" "o " "wo" "rl" "d")))
  (should (equal (seq-partition '() 2) '()))
  (should (equal (seq-partition '(1 2 3) -1) '())))

(ert-deftest test-seq-group-by ()
  (with-test-sequences (seq '(1 2 3 4))
   (should (equal (seq-group-by #'test-sequences-oddp seq)
                  '((t 1 3) (nil 2 4)))))
  (should (equal (seq-group-by #'car '((a 1) (b 3) (c 4) (a 2)))
                 '((b (b 3)) (c (c 4)) (a (a 1) (a 2))))))

(ert-deftest test-seq-reverse ()
  (with-test-sequences (seq '(1 2 3 4))
    (should (same-contents-p (seq-reverse seq) '(4 3 2 1)))
    (should (equal (type-of (seq-reverse seq))
                   (type-of seq)))))

(ert-deftest test-seq-into ()
  (let* ((vector [1 2 3])
         (list (seq-into vector 'list)))
    (should (same-contents-p vector list))
    (should (listp list)))
  (let* ((list '(hello world))
         (vector (seq-into list 'vector)))
    (should (same-contents-p vector list))
    (should (vectorp vector)))
  (let* ((string "hello")
         (list (seq-into string 'list)))
    (should (same-contents-p string list))
    (should (stringp string)))
  (let* ((string "hello")
         (vector (seq-into string 'vector)))
    (should (same-contents-p string vector))
    (should (stringp string)))
  (let* ((list nil)
         (vector (seq-into list 'vector)))
    (should (same-contents-p list vector))
    (should (vectorp vector))))

(ert-deftest test-seq-union ()
  (let ((v1 '(1 2 3))
        (v2 '(3 5)))
   (should (same-contents-p (seq-union v1 v2)
                            '(1 2 3 5))))

  (let ((v1 '(1 2 3 4 5 6))
        (v2 '(4 5 6 7 8 9)))
   (should (same-contents-p (seq-union v1 v2)
                            '(1 2 3 4 5 6 7 8 9))))

  (let ((v1 [1 2 3 4 5])
        (v2 [4 5 6 "a"]))
   (should (same-contents-p (seq-union v1 v2)
                            '(1 2 3 4 5 6 "a"))))

  (let ((v1 '("a" "b" "c"))
        (v2 '("f" "c" "e" "a")))
   (should (same-contents-p (seq-union v1 v2)
                            '("a" "b" "c" "f" "e"))))

  (let ((v1 '("a"))
        (v2 '("a"))
        (testfn #'eq))
   (should (same-contents-p (seq-union v1 v2 testfn)
                            '("a" "a")))))

(ert-deftest test-seq-intersection ()
  (let ((v1 [2 3 4 5])
        (v2 [1 3 5 6 7]))
    (should (same-contents-p (seq-intersection v1 v2)
                             '(3 5))))
  (let ((l1 '(2 3 4 5))
        (l2 '(1 3 5 6 7)))
    (should (same-contents-p (seq-intersection l1 l2)
                             '(3 5))))
  (let ((v1 [2 4 6])
        (v2 [1 3 5]))
    (should (seq-empty-p (seq-intersection v1 v2)))))

(ert-deftest test-seq-difference ()
  (let ((v1 [2 3 4 5])
        (v2 [1 3 5 6 7]))
    (should (same-contents-p (seq-difference v1 v2)
                             '(2 4))))
  (let ((l1 '(2 3 4 5))
        (l2 '(1 3 5 6 7)))
    (should (same-contents-p (seq-difference l1 l2)
                             '(2 4))))
  (let ((v1 [2 4 6])
        (v2 [2 4 6]))
    (should (seq-empty-p (seq-difference v1 v2)))))

(ert-deftest test-seq-let ()
  (with-test-sequences (seq '(1 2 3 4))
    (seq-let (a b c d e) seq
      (should (= a 1))
      (should (= b 2))
      (should (= c 3))
      (should (= d 4))
      (should (null e)))
    (seq-let (a b &rest others) seq
      (should (= a 1))
      (should (= b 2))
      (should (same-contents-p others (seq-drop seq 2)))))
  (let ((seq '(1 (2 (3 (4))))))
    (seq-let (_ (_ (_ (a)))) seq
      (should (= a 4))))
  (let ((seq nil))
    (seq-let (a b c) seq
      (should (null a))
      (should (null b))
      (should (null c)))))

(ert-deftest test-seq-setq ()
  (with-test-sequences (seq '(1 2 3 4))
    (let (a b c d e)
      (seq-setq (a b c d e) seq)
      (should (= a 1))
      (should (= b 2))
      (should (= c 3))
      (should (= d 4))
      (should (null e)))
    (let (a b others)
      (seq-setq (a b &rest others) seq)
      (should (= a 1))
      (should (= b 2))
      (should (same-contents-p others (seq-drop seq 2)))))
  (let ((a)
        (seq '(1 (2 (3 (4))))))
    (seq-setq (_ (_ (_ (a)))) seq)
    (should (= a 4)))
  (let ((seq nil) a b c)
    (seq-setq (a b c) seq)
    (should (null a))
    (should (null b))
    (should (null c))))

(ert-deftest test-seq-min-max ()
  (with-test-sequences (seq '(4 5 3 2 0 4))
    (should (= (seq-min seq) 0))
    (should (= (seq-max seq) 5))))

(ert-deftest test-seq-into-sequence ()
  (with-test-sequences (seq '(1 2 3))
    (should (eq seq (seq-into-sequence seq)))
    (should-error (seq-into-sequence 2))))

(ert-deftest test-seq-position ()
  (with-test-sequences (seq '(2 4 6))
    (should (null (seq-position seq 1)))
    (should (= (seq-position seq 4) 1)))
  (let ((seq '(a b c)))
    (should (null (seq-position seq 'd #'eq)))
    (should (= (seq-position seq 'a #'eq) 0))
    (should (null (seq-position seq (make-symbol "a") #'eq)))))

(ert-deftest test-seq-positions ()
  (with-test-sequences (seq '(1 2 3 1 4))
    (should (equal '(0 3) (seq-positions seq 1)))
    (should (seq-empty-p (seq-positions seq 9))))
  (with-test-sequences (seq '(11 5 7 12 9 15))
    (should (equal '(0 3 5) (seq-positions seq 10 #'>=)))))

(ert-deftest test-seq-sort-by ()
  (let ((seq ["x" "xx" "xxx"]))
    (should (equal (seq-sort-by #'seq-length #'> seq)
                   ["xxx" "xx" "x"]))))

(ert-deftest test-seq-random-elt-take-all ()
  (let ((seq '(a b c d e))
        elts)
    (dotimes (_ 1000)
      (let ((random-elt (seq-random-elt seq)))
        (cl-pushnew random-elt elts)))
    (should (= 5 (length elts)))))

(ert-deftest test-seq-random-elt-signal-on-empty ()
  (should-error (seq-random-elt nil))
  (should-error (seq-random-elt []))
  (should-error (seq-random-elt "")))

(ert-deftest test-seq-mapn-circular-lists ()
  (let ((l1 '#1=(1 . #1#)))
    (should (equal (seq-mapn #'+ '(3 4 5 7) l1)
                   '(4 5 6 8)))))

(ert-deftest test-seq-into-and-identity ()
  (let ((lst '(1 2 3))
        (vec [1 2 3])
        (str "foo bar"))
    (should (eq (seq-into lst 'list) lst))
    (should (eq (seq-into vec 'vector) vec))
    (should (eq (seq-into str 'string) str))))

(ert-deftest test-seq-first ()
  (let ((lst '(1 2 3))
        (vec [1 2 3]))
    (should (eq (seq-first lst) 1))
    (should (eq (seq-first vec) 1))))

(ert-deftest test-seq-rest ()
  (let ((lst '(1 2 3))
        (vec [1 2 3]))
    (should (equal (seq-rest lst) '(2 3)))
    (should (equal (seq-rest vec) [2 3]))))

;; Regression tests for bug#34852
(progn
  (ert-deftest test-seq-intersection-with-nil ()
    (should (equal (seq-intersection '(1 2 nil) '(1 nil)) '(1 nil))))

  (ert-deftest test-seq-set-equal-p-with-nil ()
    (should (seq-set-equal-p '("a" "b" nil)
                             '(nil "b" "a"))))

  (ert-deftest test-difference-with-nil ()
    (should (equal (seq-difference '(1 nil) '(2 nil))
                   '(1)))))

(ert-deftest test-seq-split ()
  (let ((seq [0 1 2 3 4 5 6 7 8 9 10]))
    (should (equal seq (car (seq-split seq 20))))
    (should (equal seq (car (seq-split seq 11))))
    (should (equal (seq-split seq 10)
                   '([0 1 2 3 4 5 6 7 8 9] [10])))
    (should (equal (seq-split seq 5)
                   '([0 1 2 3 4] [5 6 7 8 9] [10])))
    (should (equal (seq-split seq 1)
                   '([0] [1] [2] [3] [4] [5] [6] [7] [8] [9] [10])))
    (should-error (seq-split seq 0))
    (should-error (seq-split seq -10)))
  (let ((seq '(0 1 2 3 4 5 6 7 8 9)))
    (should (equal (seq-split seq 5)
                   '((0 1 2 3 4) (5 6 7 8 9)))))
  (let ((seq "0123456789"))
    (should (equal (seq-split seq 2)
                   '("01" "23" "45" "67" "89")))
    (should (equal (seq-split seq 3)
                   '("012" "345" "678" "9")))))

(ert-deftest test-seq-uniq-list ()
  (let ((list '(1 2 3)))
    (should (equal (seq-uniq (append list list)) '(1 2 3))))
  (let ((list '(1 2 3 2 1)))
    (should (equal (seq-uniq list) '(1 2 3))))
  (let ((list (list (substring "1")
                    (substring "2")
                    (substring "3")
                    (substring "2")
                    (substring "1"))))
    (should (equal (seq-uniq list) '("1" "2" "3")))
    (should (equal (seq-uniq list #'eq) '("1" "2" "3" "2" "1"))))
  ;; Long lists have a different code path.
  (let ((list (seq-map-indexed (lambda (_ i) i)
			       (make-list 10000 nil))))
    (should (= (length list) 10000))
    (should (= (length (seq-uniq (append list list))) 10000))))

(ert-deftest test-seq-keep ()
  (should (equal (seq-keep #'cl-digit-char-p '(?6 ?a ?7))
                 '(6 7)))
  (should (equal (seq-keep #'cl-digit-char-p [?6 ?a ?7])
                 '(6 7))))

(provide 'seq-tests)
;;; seq-tests.el ends here