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      1  1.8  rillig # $NetBSD: varmod-order-shuffle.mk,v 1.8 2023/02/26 06:08:06 rillig Exp $
      2  1.1  rillig #
      3  1.2  rillig # Tests for the :Ox variable modifier, which returns the words of the
      4  1.2  rillig # variable, shuffled.
      5  1.3  rillig #
      6  1.6  rillig # The variable modifier :Ox is available since 2005-06-01.
      7  1.6  rillig #
      8  1.3  rillig # As of 2020-08-16, make uses random(3) seeded by the current time in seconds.
      9  1.8  rillig # This makes the random numbers completely predictable since the only other
     10  1.8  rillig # part of make that uses random numbers is the 'randomize-targets' mode, which
     11  1.8  rillig # is off by default.
     12  1.4  rillig #
     13  1.4  rillig # Tags: probabilistic
     14  1.3  rillig 
     15  1.7  rillig WORDS=		one two three four five six seven eight nine ten
     16  1.3  rillig 
     17  1.3  rillig # Note that 1 in every 10! trials two independently generated
     18  1.3  rillig # randomized orderings will be the same.  The test framework doesn't
     19  1.3  rillig # support checking probabilistic output, so we accept that each of the
     20  1.3  rillig # 3 :Ox tests will incorrectly fail with probability 2.756E-7, which
     21  1.3  rillig # lets the whole test fail once in 1.209.600 runs, on average.
     22  1.3  rillig 
     23  1.3  rillig # Create two shuffles using the := assignment operator.
     24  1.7  rillig shuffled1:=	${WORDS:Ox}
     25  1.7  rillig shuffled2:=	${WORDS:Ox}
     26  1.3  rillig .if ${shuffled1} == ${shuffled2}
     27  1.5  rillig .  error ${shuffled1} == ${shuffled2}
     28  1.3  rillig .endif
     29  1.3  rillig 
     30  1.3  rillig # Sorting the list before shuffling it has no effect.
     31  1.7  rillig shuffled1:=	${WORDS:O:Ox}
     32  1.7  rillig shuffled2:=	${WORDS:O:Ox}
     33  1.3  rillig .if ${shuffled1} == ${shuffled2}
     34  1.5  rillig .  error ${shuffled1} == ${shuffled2}
     35  1.3  rillig .endif
     36  1.1  rillig 
     37  1.3  rillig # Sorting after shuffling must produce the original numbers.
     38  1.7  rillig sorted:=	${WORDS:Ox:O}
     39  1.7  rillig .if ${sorted} != ${WORDS:O}
     40  1.7  rillig .  error ${sorted} != ${WORDS:O}
     41  1.3  rillig .endif
     42  1.1  rillig 
     43  1.1  rillig all:
     44