1# $NetBSD: varmod-order-shuffle.mk,v 1.3 2020/08/16 20:43:01 rillig Exp $ 2# 3# Tests for the :Ox variable modifier, which returns the words of the 4# variable, shuffled. 5# 6# As of 2020-08-16, make uses random(3) seeded by the current time in seconds. 7# This makes the random numbers completely predictable since there is no other 8# part of make that uses random numbers. 9 10NUMBERS= one two three four five six seven eight nine ten 11 12# Note that 1 in every 10! trials two independently generated 13# randomized orderings will be the same. The test framework doesn't 14# support checking probabilistic output, so we accept that each of the 15# 3 :Ox tests will incorrectly fail with probability 2.756E-7, which 16# lets the whole test fail once in 1.209.600 runs, on average. 17 18# Create two shuffles using the := assignment operator. 19shuffled1:= ${NUMBERS:Ox} 20shuffled2:= ${NUMBERS:Ox} 21.if ${shuffled1} == ${shuffled2} 22.error ${shuffled1} == ${shuffled2} 23.endif 24 25# Sorting the list before shuffling it has no effect. 26shuffled1:= ${NUMBERS:O:Ox} 27shuffled2:= ${NUMBERS:O:Ox} 28.if ${shuffled1} == ${shuffled2} 29.error ${shuffled1} == ${shuffled2} 30.endif 31 32# Sorting after shuffling must produce the original numbers. 33sorted:= ${NUMBERS:Ox:O} 34.if ${sorted} != ${NUMBERS:O} 35.error ${sorted} != ${NUMBERS:O} 36.endif 37 38all: 39 @:; 40