source: vendor/perl/5.8.8/t/op/cmp.t

#!./perl

BEGIN {
       chdir 't' if -d 't';
       @INC = '../lib';
}

# 2s complement assumption. Won't break test, just makes the internals of
# the SVs less interesting if were not on 2s complement system.
my $uv_max = ~0;
my $uv_maxm1 = ~0 ^ 1;
my $uv_big = $uv_max;
$uv_big = ($uv_big - 20000) | 1;
my ($iv0, $iv1, $ivm1, $iv_min, $iv_max, $iv_big, $iv_small);
$iv_max = $uv_max; # Do copy, *then* divide
$iv_max /= 2;
$iv_min = $iv_max;
{
  use integer;
  $iv0 = 2 - 2;
  $iv1 = 3 - 2;
  $ivm1 = 2 - 3;
  $iv_max -= 1;
  $iv_min += 0;
  $iv_big = $iv_max - 3;
  $iv_small = $iv_min + 2;
}
my $uv_bigi = $iv_big;
$uv_bigi |= 0x0;

my @array = qw(perl rules);

# Seems one needs to perform the maths on 'Inf' to get the NV correctly primed.
@FOO = ('s', 'N/A', 'a', 'NaN', -1, undef, 0, 1, 3.14, 1e37, 0.632120558, -.5,
        'Inf'+1, '-Inf'-1, 0x0, 0x1, 0x5, 0xFFFFFFFF, $uv_max, $uv_maxm1,
        $uv_big, $uv_bigi, $iv0, $iv1, $ivm1, $iv_min, $iv_max, $iv_big,
        $iv_small, \$array[0], \$array[0], \$array[1], \$^X);

$expect = 7 * ($#FOO+2) * ($#FOO+1);
print "1..$expect\n";

sub nok ($$$$$$$$) {
  my ($test, $left, $threeway, $right, $result, $i, $j, $boolean) = @_;
  $result = defined $result ? "'$result'" : 'undef';
  print "not ok $test # ($left <=> $right) gives: $result \$i=$i \$j=$j, $boolean disagrees\n";
}

my $ok = 0;
for my $i (0..$#FOO) {
    for my $j ($i..$#FOO) {
        $ok++;
        # Comparison routines may convert these internally, which would change
        # what is used to determine the comparison on later runs. Hence copy
        my ($i1, $i2, $i3, $i4, $i5, $i6, $i7, $i8, $i9, $i10,
            $i11, $i12, $i13, $i14, $i15, $i16, $i17) =
          ($FOO[$i], $FOO[$i], $FOO[$i], $FOO[$i], $FOO[$i], $FOO[$i],
           $FOO[$i], $FOO[$i], $FOO[$i], $FOO[$i], $FOO[$i], $FOO[$i],
           $FOO[$i], $FOO[$i], $FOO[$i], $FOO[$i], $FOO[$i]);
        my ($j1, $j2, $j3, $j4, $j5, $j6, $j7, $j8, $j9, $j10,
            $j11, $j12, $j13, $j14, $j15, $j16, $j17) =
          ($FOO[$j], $FOO[$j], $FOO[$j], $FOO[$j], $FOO[$j], $FOO[$j],
           $FOO[$j], $FOO[$j], $FOO[$j], $FOO[$j], $FOO[$j], $FOO[$j],
           $FOO[$j], $FOO[$j], $FOO[$j], $FOO[$j], $FOO[$j]);
        my $cmp = $i1 <=> $j1;
        if (!defined($cmp) ? !($i2 < $j2)
            : ($cmp == -1 && $i2 < $j2 ||
               $cmp == 0  && !($i2 < $j2) ||
               $cmp == 1  && !($i2 < $j2)))
        {
            print "ok $ok\n";
        }
        else {
            nok ($ok, $i3, '<=>', $j3, $cmp, $i, $j, '<');
        }
        $ok++;
        if (!defined($cmp) ? !($i4 == $j4)
            : ($cmp == -1 && !($i4 == $j4) ||
               $cmp == 0  && $i4 == $j4 ||
               $cmp == 1  && !($i4 == $j4)))
        {
            print "ok $ok\n";
        }
        else {
            nok ($ok, $i3, '<=>', $j3, $cmp, $i, $j, '==');
        }
        $ok++;
        if (!defined($cmp) ? !($i5 > $j5)
            : ($cmp == -1 && !($i5 > $j5) ||
               $cmp == 0  && !($i5 > $j5) ||
               $cmp == 1  && ($i5 > $j5)))
        {
            print "ok $ok\n";
        }
        else {
            nok ($ok, $i3, '<=>', $j3, $cmp, $i, $j, '>');
        }
        $ok++;
        if (!defined($cmp) ? !($i6 >= $j6)
            : ($cmp == -1 && !($i6 >= $j6) ||
               $cmp == 0  && $i6 >= $j6 ||
               $cmp == 1  && $i6 >= $j6))
        {
            print "ok $ok\n";
        }
        else {
            nok ($ok, $i3, '<=>', $j3, $cmp, $i, $j, '>=');
        }
        $ok++;
        # OK, so the docs are wrong it seems. NaN != NaN
        if (!defined($cmp) ? ($i7 != $j7)
            : ($cmp == -1 && $i7 != $j7 ||
               $cmp == 0  && !($i7 != $j7) ||
               $cmp == 1  && $i7 != $j7))
        {
            print "ok $ok\n";
        }
        else {
            nok ($ok, $i3, '<=>', $j3, $cmp, $i, $j, '!=');
        }
        $ok++;
        if (!defined($cmp) ? !($i8 <= $j8)
            : ($cmp == -1 && $i8 <= $j8 ||
               $cmp == 0  && $i8 <= $j8 ||
               $cmp == 1  && !($i8 <= $j8)))
        {
            print "ok $ok\n";
        }
        else {
            nok ($ok, $i3, '<=>', $j3, $cmp, $i, $j, '<=');
        }
        $ok++;
        my $pmc =  $j16 <=> $i16; # cmp it in reverse
        # Should give -ve of other answer, or undef for NaNs
        # a + -a should be zero. not zero is truth. which avoids using ==
        if (defined($cmp) ? !($cmp + $pmc) : !defined $pmc)
        {
            print "ok $ok\n";
        }
        else {
            nok ($ok, $i3, '<=>', $j3, $cmp, $i, $j, '<=> transposed');
        }


        # String comparisons
        $ok++;
        $cmp = $i9 cmp $j9;
        if ($cmp == -1 && $i10 lt $j10 ||
            $cmp == 0  && !($i10 lt $j10) ||
            $cmp == 1  && !($i10 lt $j10))
        {
            print "ok $ok\n";
        }
        else {
            nok ($ok, $i3, 'cmp', $j3, $cmp, $i, $j, 'lt');
        }
        $ok++;
        if ($cmp == -1 && !($i11 eq $j11) ||
            $cmp == 0  && ($i11 eq $j11) ||
            $cmp == 1  && !($i11 eq $j11))
        {
            print "ok $ok\n";
        }
        else {
            nok ($ok, $i3, 'cmp', $j3, $cmp, $i, $j, 'eq');
        }
        $ok++;
        if ($cmp == -1 && !($i12 gt $j12) ||
            $cmp == 0  && !($i12 gt $j12) ||
            $cmp == 1  && ($i12 gt $j12))
        {
            print "ok $ok\n";
        }
        else {
            nok ($ok, $i3, 'cmp', $j3, $cmp, $i, $j, 'gt');
        }
        $ok++;
        if ($cmp == -1 && $i13 le $j13 ||
            $cmp == 0  && ($i13 le $j13) ||
            $cmp == 1  && !($i13 le $j13))
        {
            print "ok $ok\n";
        }
        else {
            nok ($ok, $i3, 'cmp', $j3, $cmp, $i, $j, 'le');
        }
        $ok++;
        if ($cmp == -1 && ($i14 ne $j14) ||
            $cmp == 0  && !($i14 ne $j14) ||
            $cmp == 1  && ($i14 ne $j14))
        {
            print "ok $ok\n";
        }
        else {
            nok ($ok, $i3, 'cmp', $j3, $cmp, $i, $j, 'ne');
        }
        $ok++;
        if ($cmp == -1 && !($i15 ge $j15) ||
            $cmp == 0  && ($i15 ge $j15) ||
            $cmp == 1  && ($i15 ge $j15))
        {
            print "ok $ok\n";
        }
        else {
            nok ($ok, $i3, 'cmp', $j3, $cmp, $i, $j, 'ge');
        }
        $ok++;
        $pmc =  $j17 cmp $i17; # cmp it in reverse
        # Should give -ve of other answer
        # a + -a should be zero. not zero is truth. which avoids using ==
        if (!($cmp + $pmc))
        {
            print "ok $ok\n";
        }
        else {
            nok ($ok, $i3, '<=>', $j3, $cmp, $i, $j, 'cmp transposed');
        }
    }
}