Re: New assertions in Ruby

[Adrian Howard]

On 13 Feb 2008, at 00:10, Michael G Schwern wrote:
[snip]
Data::Dump::Streamer can decompile a code reference, complete with  
attached lexicals.  But as has been pointed out by Yuval, the real  
trick is to show the value of all variables used in the block.
[snip]
Yeah... hadn't considered globals, let alone inlined methods. This  
hacked on to T::E:

    sub ok_if (&;$) {
        my ( $coderef, $description ) = @_;
        my $ok = eval { $coderef->() };
        my $exception = $@;
        $Tester->ok( $ok, $description );
        unless ( $ok ) {
            $Tester->diag( _exception_as_string( "died:",  
$exception ) )
                if _is_exception( $exception );
            $Tester->diag( DumpVars( code => $coderef )->Out );
        }
        $@ = $exception;
        return $ok;
    }

called like:

    my $answer = 41;
    ok_if { $answer == 42 };

gives me:

    not ok 1
    #   Failed test at t/ok_if.t line 10.
    # my ($answer);
    # $answer = 41;
    # $code = sub {
    #           use warnings;
    #           use strict 'refs';
    #           $answer == 42;
    #         };

which isn't _too_ shabby, but doesn't help much with things like:

    ok_if { Foo->new->answer == 42 };

or

    ok_if { $Some_dynamic_var == 42 };

So I don't really think it's worth pursuing.

Cheers,

Adrian