test/src/floatfns-tests.el

   1 ;;; floatfns-tests.el --- tests for floating point operations
   2
   3 ;; Copyright 2017-2018 Free Software Foundation, Inc.
   4
   5 ;; This file is part of GNU Emacs.
   6
   7 ;; GNU Emacs is free software: you can redistribute it and/or modify
   8 ;; it under the terms of the GNU General Public License as published by
   9 ;; the Free Software Foundation, either version 3 of the License, or
  10 ;; (at your option) any later version.
  11
  12 ;; GNU Emacs is distributed in the hope that it will be useful,
  13 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 ;; GNU General Public License for more details.
  16
  17 ;; You should have received a copy of the GNU General Public License
  18 ;; along with GNU Emacs.  If not, see <https://www.gnu.org/licenses/>.
  19
  20 (require 'ert)
  21
  22 (ert-deftest divide-extreme-sign ()
  23   (should (= (ceiling most-negative-fixnum -1.0) (- most-negative-fixnum)))
  24   (should (= (floor most-negative-fixnum -1.0) (- most-negative-fixnum)))
  25   (should (= (round most-negative-fixnum -1.0) (- most-negative-fixnum)))
  26   (should (= (truncate most-negative-fixnum -1.0) (- most-negative-fixnum))))
  27
  28 (ert-deftest logb-extreme-fixnum ()
  29   (should (= (logb most-negative-fixnum) (1+ (logb most-positive-fixnum)))))
  30
  31 (ert-deftest fround-fixnum ()
  32   (should-error (ffloor 0) :type 'wrong-type-argument)
  33   (should-error (fceiling 0) :type 'wrong-type-argument)
  34   (should-error (ftruncate 0) :type 'wrong-type-argument)
  35   (should-error (fround 0) :type 'wrong-type-argument))
  36
  37 (ert-deftest bignum-to-float ()
  38   ;; 122 because we want to go as big as possible to provoke a rounding error,
  39   ;; but not too big: 2**122 < 10**37 < 2**123, and the C standard says
  40   ;; 10**37 <= DBL_MAX so 2**122 cannot overflow as a double.
  41   (let ((a (1- (ash 1 122))))
  42     (should (or (eql a (1- (floor (float a))))
  43                 (eql a (floor (float a))))))
  44   (should (eql (float (+ most-positive-fixnum 1))
  45                (+ (float most-positive-fixnum) 1))))
  46
  47 (ert-deftest bignum-abs ()
  48   (should (= most-positive-fixnum
  49              (- (abs most-negative-fixnum) 1))))
  50
  51 (ert-deftest bignum-expt ()
  52   (dolist (n (list most-positive-fixnum (1+ most-positive-fixnum)
  53                    most-negative-fixnum (1- most-negative-fixnum)
  54                    -2 -1 0 1 2))
  55     (should (= (expt n 0) 1))
  56     (should (= (expt n 1) n))
  57     (should (= (expt n 2) (* n n)))
  58     (should (= (expt n 3) (* n n n)))))
  59
  60 (ert-deftest bignum-logb ()
  61   (should (= (+ (logb most-positive-fixnum) 1)
  62              (logb (+ most-positive-fixnum 1)))))
  63
  64 (ert-deftest bignum-mod ()
  65   (should (= 0 (mod (1+ most-positive-fixnum) 2.0))))
  66
  67 (ert-deftest bignum-round ()
  68   (let ((ns (list (* most-positive-fixnum most-negative-fixnum)
  69                   (1- most-negative-fixnum) most-negative-fixnum
  70                   (1+ most-negative-fixnum) -2 1 1 2
  71                   (1- most-positive-fixnum) most-positive-fixnum
  72                   (1+ most-positive-fixnum)
  73                   (* most-positive-fixnum most-positive-fixnum))))
  74     (dolist (n ns)
  75       (should (= n (ceiling n)))
  76       (should (= n (floor n)))
  77       (should (= n (round n)))
  78       (should (= n (truncate n)))
  79       (let ((-n (- n))
  80             (f (float n))
  81             (-f (- (float n))))
  82         (should (= 1 (round n f) (round -n -f) (round f n) (round -f -n)))
  83         (should (= -1 (round -n f) (round n -f) (round f -n) (round -f n))))
  84       (dolist (d ns)
  85         (let ((q (/ n d))
  86               (r (% n d))
  87               (same-sign (eq (< n 0) (< d 0))))
  88           (should (= (ceiling n d)
  89                      (+ q (if (and same-sign (not (zerop r))) 1 0))))
  90           (should (= (floor n d)
  91                      (- q (if (and (not same-sign) (not (zerop r))) 1 0))))
  92           (should (= (truncate n d) q))
  93           (let ((cdelta (abs (- n (* d (ceiling n d)))))
  94                 (fdelta (abs (- n (* d (floor n d)))))
  95                 (rdelta (abs (- n (* d (round n d))))))
  96             (should (<= rdelta cdelta))
  97             (should (<= rdelta fdelta))
  98             (should (if (zerop r)
  99                         (= 0 cdelta fdelta rdelta)
 100                       (or (/= cdelta fdelta)
 101                           (zerop (% (round n d) 2)))))))))))
 102
 103 (ert-deftest special-round ()
 104   (let ((ns '(-1e+INF 1e+INF -1 1 -1e+NaN 1e+NaN)))
 105     (dolist (n ns)
 106       (unless (<= (abs n) 1)
 107         (should-error (ceiling n))
 108         (should-error (floor n))
 109         (should-error (round n))
 110         (should-error (truncate n)))
 111       (dolist (d ns)
 112         (unless (<= (abs (/ n d)) 1)
 113           (should-error (ceiling n d))
 114           (should-error (floor n d))
 115           (should-error (round n d))
 116           (should-error (truncate n d)))))))
 117
 118 (ert-deftest big-round ()
 119   (should (= (floor 54043195528445955 3)
 120              (floor 54043195528445955 3.0))))
 121
 122 (provide 'floatfns-tests)