Test::NiceDump(3)

NAME
Test::NiceDump - let's have a nice and human readable dump of our objects!

VERSION
version 1.0.1

SYNOPSIS
    use Test::Deep;
    use Test::NiceDump 'nice_explain';

    cmp_deeply($got,$expected,'it works')
        or nice_explain($got,$expected);

DESCRIPTION
This module uses "Data::Dump::Filtered" and a set of sensible filters to dump test data in a more readable way.

For example, "DateTime" objects get printed in the full ISO 8601 format, and "DBIx::Class::Row" objects get printed as hashes of their inflated columns.

FUNCTIONS

  "nice_dump"
    my $dumped_string = nice_dump $data;

Serialise $data in a nice, readable way.

  "nice_explain"
    nice_explain $data;
    nice_explain $data, $comparator;

Calls ""nice_dump"" on $data and $comparator (if provided), and uses "diag" to provide test failure feedback with the dumped strings.

HOW TO ADD FILTERS
If the built-in filtering of input data is not enough for you, you can add extra filters. A filter is a coderef that takes a single argument (the value to be dumped), and returns either:

nothing at all
    to signal that it won't handle this particular value

any single value
    which will be dumped instead

Let's say you have a class "My::Class", and you don't want its instances to be dumped directly (maybe they contain cached data that's not very useful to see). That class may have a "as_data_for_log" method that returns only the important bits of data (as a hashref, probably), so you want the return value of that method to be dumped instead. You could say:

    use Safe::Isa;

    Test::NiceDump::add_filter(
        my_filter => sub {
            $_[0]->$_isa('My::Class')
                ? $_[0]->as_data_for_log
                : ();
        },
    );

or, if you want to do the same for any object with that method:

    use Safe::Isa;

    Test::NiceDump::add_filter(
        my_filter => sub { $_[0]->$_call_if_can('as_data_for_log') },
    );

  "add_filter"
  Test::NiceDump::add_filter($name => $code);

Adds a new filter. Adding a filter with an existing name overrides it.

Filters are invoked in "cmp" order of name. The names of all built-in filters match "/^Test::NiceDump::/".

Try to be specific with your checks, to avoid surprises due to the interaction of different filters.

Your filter must return nothing at all if it didn't handle the value. Failure to do so will probably lead to infinite recursion.

  "remove_filter"
  Test::NiceDump::remove_filter($name);

Removes the filter with the given name. Nothing happens if such a filter does not exist.

AUTHOR
Gianni Ceccarelli <gianni.ceccarelli@broadbean.com>

COPYRIGHT AND LICENSE
This software is copyright (c) 2019 by BroadBean UK, a CareerBuilder Company.

This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.