Altering &Test::Most::explain?

Ovid on 2008-07-24T07:03:05

In Test::Most, I have an "explain" function. This functions just like &Test::More::diag, except it only triggers in verbose mode. Thus, if you run an individual test to see its full output, you see the "explain" dialogue. When you run a full test suite, you don't. It's very handy to keep from having "messy" test suite output.

Now I'm thinking about rewriting it as follows:

sub explain {
    return unless $ENV{TEST_VERBOSE};
    if ( ref $_[0] ) {
        require Data::Dumper;
        local $Data::Dumper::Indent   = 1;
        local $Data::Dumper::Sortkeys = 1;
        Test::More::diag(Data::Dumper::Dumper(@_));
    }
    else {
        Test::More::diag(@_);
    }
}

In other words, you can forget about using Data::Dumper in your test suites just to diagnose bugs. You can do this:

my $self = Some::Object->new($id);
explain $self;

Since we rarely need to print a reference as a string, this seems right, but I wonder if I'm violating some principle of least surprise.

---

I really like the idea ..

swillert on 2008-07-24T07:54:23

.. but maybe you should even try to dump each ref in the argument list (untested):

sub explain {
  return unless $ENV{TEST_VERBOSE};
  Test::More::diag(
    map{
      ref $_ ? do {
        require Data::Dumper;
        local $Data::Dumper::Indent   = 1;
        local $Data::Dumper::Sortkeys = 1;
        Data::Dumper::Dumper($_);
      } : $_
    } @_
  );
}

This would allow for nifty stuff like:

my $self = Some::Object->new($id);
explain 'I just created', $self;

Cheers, Sebastian

Test::More::diag should do it

htoug on 2008-07-24T08:10:33

I think it is such a good idea that I would plead for it to be moved into Test::More::diag.

But as that is not likely, your idea is quite nifty og even nice.

diag Dumper

rjbs on 2008-07-28T11:57:07

After something like ten years of Perl, I still expect diag to dumper for me, so you won't be surprising me at all.