Mercurial > vim
view src/testdir/test_random.vim @ 18703:aef98a646d3e v8.1.2343
patch 8.1.2343: using time() for srand() is not very random
Commit: https://github.com/vim/vim/commit/07e4a197953d12902fb97beb48830a5323a52280
Author: Bram Moolenaar <Bram@vim.org>
Date: Tue Nov 26 12:23:30 2019 +0100
patch 8.1.2343: using time() for srand() is not very random
Problem: Using time() for srand() is not very random.
Solution: use /dev/urandom if available
| author | Bram Moolenaar <Bram@vim.org> |
|---|---|
| date | Tue, 26 Nov 2019 12:30:04 +0100 |
| parents | 128662297ddf |
| children | 2513e666aa82 |
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" Tests for srand() and rand() func Test_Rand() let r = srand(123456789) call assert_equal([123456789, 362436069, 521288629, 88675123], r) call assert_equal(3701687786, rand(r)) call assert_equal(458299110, rand(r)) call assert_equal(2500872618, rand(r)) call assert_equal(3633119408, rand(r)) call assert_equal(516391518, rand(r)) call test_settime(12341234) let s = srand() if filereadable('/dev/urandom') " using /dev/urandom call assert_notequal(s, srand()) else " using time() call assert_equal(s, srand()) call test_settime(12341235) call assert_notequal(s, srand()) endif call srand() let v = rand() call assert_notequal(v, rand()) call assert_fails('echo srand([1])', 'E745:') call assert_fails('echo rand([1, 2, 3])', 'E475:') call assert_fails('echo rand([[1], 2, 3, 4])', 'E475:') call assert_fails('echo rand([1, [2], 3, 4])', 'E475:') call assert_fails('echo rand([1, 2, [3], 4])', 'E475:') call assert_fails('echo rand([1, 2, 3, [4]])', 'E475:') call test_settime(0) endfunc