1# $NetBSD: varmod-order-shuffle.mk,v 1.8 2023/02/26 06:08:06 rillig Exp $
2#
3# Tests for the :Ox variable modifier, which returns the words of the
4# variable, shuffled.
5#
6# The variable modifier :Ox is available since 2005-06-01.
7#
8# As of 2020-08-16, make uses random(3) seeded by the current time in seconds.
9# This makes the random numbers completely predictable since the only other
10# part of make that uses random numbers is the 'randomize-targets' mode, which
11# is off by default.
12#
13# Tags: probabilistic
14
15WORDS=		one two three four five six seven eight nine ten
16
17# Note that 1 in every 10! trials two independently generated
18# randomized orderings will be the same.  The test framework doesn't
19# support checking probabilistic output, so we accept that each of the
20# 3 :Ox tests will incorrectly fail with probability 2.756E-7, which
21# lets the whole test fail once in 1.209.600 runs, on average.
22
23# Create two shuffles using the := assignment operator.
24shuffled1:=	${WORDS:Ox}
25shuffled2:=	${WORDS:Ox}
26.if ${shuffled1} == ${shuffled2}
27.  error ${shuffled1} == ${shuffled2}
28.endif
29
30# Sorting the list before shuffling it has no effect.
31shuffled1:=	${WORDS:O:Ox}
32shuffled2:=	${WORDS:O:Ox}
33.if ${shuffled1} == ${shuffled2}
34.  error ${shuffled1} == ${shuffled2}
35.endif
36
37# Sorting after shuffling must produce the original numbers.
38sorted:=	${WORDS:Ox:O}
39.if ${sorted} != ${WORDS:O}
40.  error ${sorted} != ${WORDS:O}
41.endif
42
43all:
44