So now you've got to invent names for all your tests. Just so you can search for that name to find the test?

That is asinine make-work.

If I use die. It automatically "names" the test, with the file and line number.

As I have already said, Test::Simple/Test::More, etc give you the file and line number out of the box, without needing to name the test.

But consider:

die "reason";
# versus just
die;

[download]

If you ever provide an argument for die, you've just provided a name for a test. Is that "asinine make-work"?

Besides which, if the line in question is in a loop, a file name and line number might not be enough - a name can be very useful to figure out what's gone wrong.

{
   package Maths;
   sub factorial { my $n = int(pop); return $n if $n<2; $n * factorial
+($n - 1) }
}

use Test::More;
my @expected = qw/ 0 1 2 6 24 100 720 /;
plan tests => scalar @expected;
is(Maths::factorial($_), $expected[$_], "Factorial of $_") for 0 .. $#
+expected;

[download]

A failure on line 8 doesn't give you a clue what test has failed. A failure on line 8 named "Factorial of 5" does.

$ perl factorial.t
1..7
ok 1 - Factorial of 0
ok 2 - Factorial of 1
ok 3 - Factorial of 2
ok 4 - Factorial of 3
ok 5 - Factorial of 4
not ok 6 - Factorial of 5
#   Failed test 'Factorial of 5'
#   at factorial.t line 8.
#          got: '120'
#     expected: '100'
ok 7 - Factorial of 6
# Looks like you failed 1 test of 7.

In this case, looking at the output, it's clear where the failure is, and checking the factorial of 5 on a calculator, it's the expected result which is in fact incorrect - my ultra-useful Maths package appears to be bug-free. Though an improvement might be to die if called with a negative number.

{
    package Maths;
    sub factorial {
        my $n = int(shift);
        die "does not compute" if $n<0;
        return $n if $n<2;
        $n * factorial($n - 1);
    }
}

use Test::More;
use Test::Exception;

my @results = qw/ 0 1 2 6 24 120 720 /;
for (0 .. $#results)
{
    lives_and { is Maths::factorial($_), $results[$_] } "Factorial of 
+$_";
}

dies_ok { Maths::factorial(-2) } "Factorial of negative number";

done_testing;

[download]
ok 1 - Factorial of 0
ok 2 - Factorial of 1
ok 3 - Factorial of 2
ok 4 - Factorial of 3
ok 5 - Factorial of 4
ok 6 - Factorial of 5
ok 7 - Factorial of 6
ok 8 - Factorial of negative number
1..8

In reply to Re^8: Developing a module, how do you do it ? by tobyink
in thread Developing a module, how do you do it ? by mascip

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