RFC: Refactoring the lib/perl5db.t test script (for the "perl -d"front-end).

Hi all,

I've been adding tests to the Perl debugger in some of my github branches, such
as:

https://github.com/shlomif/perl/tree/perl-d-add-tests-5-while-cherry-picking-commits

I hope the remaining commits gets applied soon, but as I was adding the code
I noticed that I've been writing very similar code times and again:

[CODE]
{
    rc(<<'EOF');
&parse_options("NonStop=0 TTY=db.out LineInfo=db.out");

sub afterinit {
    push (@DB::typeahead,
    'n uncalled_subroutine()',
    'c',
    'q',
    );

}
EOF

    my $output = runperl(switches => [ '-d', ], stderr => 1, progfile => '../lib/perl5db/t/uncalled-subroutine');

    like ($output, 
        qr/<1,2,3,4,5>\n/,
        'uncalled_subroutine was called after n EXPR()',
        );

}
[/CODE]

And:

[CODE]
# Tests for "T" (stack trace).
{
    rc(<<'EOF');
&parse_options("NonStop=0 TTY=db.out LineInfo=db.out");

sub afterinit {
    push (@DB::typeahead,
    'c baz',
    'T',
    'q',
    );

}
EOF

    my $prog_fn = '../lib/perl5db/t/rt-104168';
    my $output = runperl(switches => [ '-d', ], stderr => 1, progfile => $prog_fn,);

    my $re_text = join('',
        map {
        sprintf(
            "%s = %s\\(\\) called from file " .
            "'" . quotemeta($prog_fn) . "' line %s\\n",
            (map { quotemeta($_) } @$_)
            )
        } 
        (
            ['.', 'main::baz', 14,],
            ['.', 'main::bar', 9,],
            ['.', 'main::foo', 6]
        )
    );
    like(_out_contents(), 
        # qr/^0\s+HASH\([^\)]+\)\n\s+500 => 600\n/,
        qr/^$re_text/ms,
        "T command test."
    );
}
[/CODE]

I've been thinking that it would be a good idea to refactor it into a class
where:

1. The @DB::typeahead commands will be given as a list of Perl strings, which
would be encoded and quoted in the call to rc().

2. There will be two fields for $output and _out_contents() with methods that
can be used to match them with regular expressions (ultimately calling like).

3. The final "q" command will be added by default with a flag to suppress it.

The topic of whether duplication in automated tests is a good idea is
controversial (see for example
http://tech.groups.yahoo.com/group/extremeprogramming/message/146255 ),
but I feel that a good API for testing the debugger will be a good idea here
and will facilitate writing subsequent tests.

What are your thoughts?

Regards,

	Shlomi Fish

-- 
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• RFC: Refactoring the lib/perl5db.t test script (for the "perl -d"front-end). by Shlomi Fish