1#!./perl 2 3# This tests the behavior of sort() under the different 'use sort' forms. 4# Algorithm by John P. Linderman. 5 6my ($BigWidth, $BigEnough, $RootWidth, $ItemFormat, @TestSizes, $WellSoaked); 7 8BEGIN { 9 chdir 't' if -d 't'; 10 @INC = qw(../lib); 11 $BigWidth = 6; # Digits in $BigEnough-1 12 $BigEnough = 10**$BigWidth; # Largest array we'll attempt 13 $RootWidth = int(($BigWidth+1)/2); # Digits in sqrt($BigEnough-1) 14 $ItemFormat = "%0${RootWidth}d%0${BigWidth}d"; # Array item format 15 @TestSizes = (0, 1, 2); # Small special cases 16 # Testing all the way up to $BigEnough takes too long 17 # for casual testing. There are some cutoffs (~256) 18 # in pp_sort that should be tested, but 10_000 is ample. 19 $WellSoaked = 10_000; # <= $BigEnough 20 for (my $ts = 3; $ts < $WellSoaked; $ts *= 10**(1/3)) { 21 push(@TestSizes, int($ts)); # about 3 per decade 22 } 23} 24 25use strict; 26use warnings; 27 28use Test::More tests => @TestSizes * 2 # sort() tests 29 * 3 # number of pragmas to test 30 + 10; # tests for sort::current 31 32# Generate array of specified size for testing sort. 33# 34# We ensure repeated items, where possible, by drawing the $size items 35# from a pool of size sqrt($size). Each randomly chosen item is 36# tagged with the item index, so we can detect original input order, 37# and reconstruct the original array order. 38 39sub genarray { 40 my $size = int(shift); # fractions not welcome 41 my ($items, $i); 42 my @a; 43 44 if ($size < 0) { $size = 0; } # avoid complexity with sqrt 45 elsif ($size > $BigEnough) { $size = $BigEnough; } 46 $#a = $size - 1; # preallocate array 47 $items = int(sqrt($size)); # number of distinct items 48 for ($i = 0; $i < $size; ++$i) { 49 $a[$i] = sprintf($ItemFormat, int($items * rand()), $i); 50 } 51 return \@a; 52} 53 54 55# Check for correct order (including stability) 56 57sub checkorder { 58 my $aref = shift; 59 my $status = ''; # so far, so good 60 my ($i, $disorder); 61 62 for ($i = 0; $i < $#$aref; ++$i) { 63 # Equality shouldn't happen, but catch it in the contents check 64 next if ($aref->[$i] le $aref->[$i+1]); 65 $disorder = (substr($aref->[$i], 0, $RootWidth) eq 66 substr($aref->[$i+1], 0, $RootWidth)) ? 67 "Instability" : "Disorder"; 68 # Keep checking if merely unstable... disorder is much worse. 69 $status = 70 "$disorder at element $i between $aref->[$i] and $aref->[$i+1]"; 71 last unless ($disorder eq "Instability"); 72 } 73 return $status; 74} 75 76 77# Verify that the two array refs reference identical arrays 78 79sub checkequal { 80 my ($aref, $bref) = @_; 81 my $status = ''; 82 my $i; 83 84 if (@$aref != @$bref) { 85 $status = "Sizes differ: " . @$aref . " vs " . @$bref; 86 } else { 87 for ($i = 0; $i < @$aref; ++$i) { 88 next if ($aref->[$i] eq $bref->[$i]); 89 $status = "Element $i differs: $aref->[$i] vs $bref->[$i]"; 90 last; 91 } 92 } 93 return $status; 94} 95 96 97# Test sort on arrays of various sizes (set up in @TestSizes) 98 99sub main { 100 my ($dothesort, $expect_unstable) = @_; 101 my ($ts, $unsorted, @sorted, $status); 102 my $unstable_num = 0; 103 104 foreach $ts (@TestSizes) { 105 $unsorted = genarray($ts); 106 # Sort only on item portion of each element. 107 # There will typically be many repeated items, 108 # and their order had better be preserved. 109 @sorted = $dothesort->(sub { substr($a, 0, $RootWidth) 110 cmp 111 substr($b, 0, $RootWidth) }, $unsorted); 112 $status = checkorder(\@sorted); 113 # Put the items back into the original order. 114 # The contents of the arrays had better be identical. 115 if ($expect_unstable && $status =~ /^Instability/) { 116 $status = ''; 117 ++$unstable_num; 118 } 119 is($status, '', "order ok for size $ts"); 120 @sorted = $dothesort->(sub { substr($a, $RootWidth) 121 cmp 122 substr($b, $RootWidth) }, \@sorted); 123 $status = checkequal(\@sorted, $unsorted); 124 is($status, '', "contents ok for size $ts"); 125 } 126 if ($expect_unstable) { 127 ok($unstable_num > 0, 'Instability ok'); 128 } 129} 130 131# Test with no pragma yet loaded. Stability is expected from default sort. 132main(sub { sort {&{$_[0]}} @{$_[1]} }, 0); 133 134# Verify that we have eliminated the segfault that could be triggered 135# by invoking a sort as part of a comparison routine. 136# No need for an explicit test. If we don't segfault, we're good. 137 138{ 139 sub dumbsort { 140 my ($a, $b) = @_; 141 use sort qw( defaults stable ); 142 my @ignore = sort (5,4,3,2,1); 143 return $a <=> $b; 144 } 145 use sort qw( defaults stable ); 146 my @nested = sort { dumbsort($a,$b) } (3,2,2,1); 147} 148 149{ 150 use sort qw(stable); 151 my $sort_current; 152 BEGIN { 153 my $a = "" ; 154 local $SIG{__WARN__} = sub {$a = $_[0]}; 155 $sort_current = sort::current(); 156 like($a, qr/\Asort::current is deprecated\b/, "sort::current warns"); 157 } 158 is($sort_current, 'stable', 'sort::current for stable'); 159 main(sub { sort {&{$_[0]}} @{$_[1]} }, 0); 160} 161 162# Tests added to check "defaults" subpragma, and "no sort" 163 164{ 165 use sort qw(defaults stable); 166 my $sort_current; 167 BEGIN { 168 my $a = "" ; 169 local $SIG{__WARN__} = sub {$a = $_[0]}; 170 $sort_current = sort::current(); 171 like($a, qr/\Asort::current is deprecated\b/, "sort::current warns"); 172 } 173 is($sort_current, 'stable', 'sort::current after defaults stable'); 174 main(sub { sort {&{$_[0]}} @{$_[1]} }, 0); 175} 176 177# Tests added to check how sort::current is deprecated 178 179{ 180 no sort qw(stable); 181 my $sort_current; 182 BEGIN { 183 my $a = "" ; 184 local $SIG{__WARN__} = sub {$a = $_[0]}; 185 $sort_current = sort::current(); 186 like($a, qr/\Asort::current is deprecated\b/, "sort::current warns"); 187 } 188 is($sort_current, 'stable', 'sort::current *always* stable'); 189} 190 191{ 192 use sort qw(defaults); 193 my $sort_current; 194 BEGIN { 195 no warnings qw(deprecated); 196 my $a = "" ; 197 local $SIG{__WARN__} = sub {$a = $_[0]}; 198 $sort_current = sort::current(); 199 is($a, "", "sort::current warning can be disabled"); 200 } 201 is($sort_current, 'stable', 'sort::current *always* stable'); 202} 203 204{ 205 use sort qw(stable); 206 my $sort_current; 207 BEGIN { 208 no warnings qw(deprecated); 209 my $a = "" ; 210 local $SIG{__WARN__} = sub {$a = $_[0]}; 211 $sort_current = sort::current(); 212 is($a, "", "sort::current warning can be disabled"); 213 } 214 is($sort_current, 'stable', 'sort::current for stable'); 215} 216