To my slight surprise, if you use Test::More:is() to compare the numbers, they are equal. I guess it depends, as Bill Clinton said, on what the definition of "is" is. In Test::More, it turns out, is is eq. Using the cmp_ok test with '==' fails, but the diagnostic is pretty unhelpful. I wonder, is there a way to get more explicit inequality diagnostics from tests?

#!/usr/bin/perl
use strict;
use warnings;
use Test::More qw(no_plan);

my $x1 = 44.7;
my $x2 = 44.9-0.2;

is($x1,$x2, "44.7 is 44.9-0.2"); #succeeds. because is uses the eq ope
+rator...
cmp_ok($x1,'==',$x2, "44.7 == 44.9-0.2"); # fails. but the diagnostic 
+isn't real helpful.
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outputs:

E:\data\learning>perl scratch.pl
ok 1 - 44.7 is 44.9-0.2
not ok 2 - 44.7 == 44.9-0.2
#     Failed test (scratch.pl at line 10)
#          got: 44.7
#     expected: 44.7
1..2
# Looks like you failed 1 tests of 2.
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