NAME
Test::Approx  compare two things for approximate equality
SYNOPSIS
use Test::Approx 'no_plan';
is_approx( 'abcd', 'abcd', 'equal strings' );
is_approx( 1234, 1234, 'equal integers' );
is_approx( 1.234, 1.234, 'equal decimal numbers' );
is_approx( '1.234000', '1.234', 'equal decimal numbers, extra zeros' );
is_approx( 1.0, 1, 'equal decimal number & integer' );
is_approx( 'abcdefgh', 'abcdefg', 'approx strings' );
is_approx( 1, 1.001, 'approx given decimal number & integer' );
is_approx( 51.60334, 51.603335, 'approx decimal numbers' );
# default Levenshtein edit tolerance is 5% of avg string length:
is_approx( 'abcdefg', 'abcgfe', 'str tolerance' ); # fail
# default difference tolerance is 5% of first number:
is_approx( 1, 1.04, 'num tolerance' ); # fail
is_approx( 1, 1.05, 'num tolerance' ); # fail
# default difference tolerance is 5% of first integer, or 1:
is_approx( 1, 2, 'int tolerance' ); # pass
is_approx( 100, 105, 'int tolerance' ); # pass
is_approx( 100, 106, 'int tolerance' ); # fail
# you can set the tolerance yourself:
is_approx( 'abcdefg', 'abcgfe', 'diff strings', '50%' ); # pass
# you can set tolerance as a number too:
is_approx( 'abcdefg', 'abcgfe', 'diff strings', 6 );
# you can force compare as string, number, or integer:
is_approx_str( '1.001', '1.901', 'pass as string' );
is_approx_num( '1.001', '1.901', 'fail as num' );
is_approx_int( '1.001', '1.901', 'pass as int' ); # not rounded!
DESCRIPTION
This module lets you test if two things are approximately equal. Yes, that sounds a bit wrong at first  surely you know if they should be equal or not? But there are actually valid cases when you don't / can't know. This module is meant for those rare cases when close is good enough.
FUNCTIONS
 is_approx( $arg1, $arg2 [, $test_name, $tolerance ] )

Tests if two scalars
$arg1
&$arg2
are approximately equal by using one of: "is_approx_str", "is_approx_num" or is_approx_int.$test_name
defaults to'arg1' =~ 'arg2'
.$tolerance
is used to determine how different the scalars can be, it defaults to5%
. It can also be set as a number representing a threshold. To determine which:$tolerance = '6%'; # threshold = calculated at 6% $tolerance = 0.06; # threshold = 0.06
See the individual functions to determine how
$tolerance
is used.  is_approx_str( $str1, $str2 [, $test_name, $tolerance ] )

Tests if
$str1
is approximately equal to$str2
by using Text::LevenshteinXS to compute the edit distance between the two strings, and comparing that to$tolerance
.$tolerance
is used to determine how many edits are allowed before the comparison test fails. If a percentage is given, the edit distance threshold will be set tox%
of the average lengths of the two strings. eg:$edit_threshold = int( $x_percent * avg(length($str1), length($str2)) );
If that's less than 0, it defaults to
1
. You can also pass$tolerance
in as an number. To avoid confusion:$tolerance = '6%'; # threshold = 6% of avg strlen $tolerance = 0.06; # threshold = int( 0.06 ) = 0
 is_approx_num( $num1, $num2 [, $test_name, $tolerance ] )

Tests if
$num1
is approximately equal to$num2
by calculating the distance between them and comparing that to$tolerance
.If
$tolerance
is a percentage, the distance threshold will be set tox%
of the first number, eg:$threshold = $x_percent * $num1;
Note that this can be 0 > $t > 1, which is probably what you want. To avoid confusion:
$tolerance = '6%'; # threshold = 6% of $num1 $tolerance = 0.06; # threshold = 0.06
 is_approx_int( $int1, $int2 [, $test_name, $tolerance ] )

Tests if
$int1
is approximately equal to$int2
by calculating the distance between them and comparing that to$tolerance
. This is slightly different to "is_approx_num" as all fractions are removed.If
$tolerance
is a percentage, the distance threshold will be set tox%
of the first integer, or 1. Eg:$threshold = int( $x_percent * $int1 )  1;
To avoid confusion:
$tolerance = '6%'; # threshold = 6% of $int1 $tolerance = 0.06; # threshold = 0.06
EXPORTS
is_approx
, is_approx_str
, is_approx_num
, is_approx_int
AUTHOR
Steve Purkis <spurkis@cpan.org>
COPYRIGHT
Copyright (c) 20082010 Steve Purkis. Released under the same terms as Perl itself.
SEE ALSO
Text::LevenshteinXS, Test::Builder
1 POD Error
The following errors were encountered while parsing the POD:
 Around line 310:
You forgot a '=back' before '=head1'