Older blog entries for kbob (starting at number 2)

Unit Testing in Perl

I read the eXtreme Programming book (Wiki:ExtremeProgrammingExplainedEmbraceChange) a while ago, and the part of XP that interests me most has been the unit testing stuff. But I couldn't get anybody else at work interested.

So now I'm working on a big, ugly Perl script (over 1,000 lines and still writing), and I decided to put unit tests into every class definition. Then I wrote some truly ugly code to find all the methods named "self_test" and execute them when the script starts up.

Well, hey, it works. I've got over 1,000 lines of working code, and I haven't had to debug anything that wasn't trivially easy to find and fix. In previous Perl projects, I've always gotten ensnared in bugs where a variable is supposed to be a ref, but it's actually a ref to a ref, or it's a ref to the wrong thing, or, ...

Perl's lack of encapsulation makes isolating the class under test easy -- if Foo::method requires a Bar as argument, I just pass in bless { }, 'Bar', instead of creating a real Bar.

Each selftest uses die to report errors. The "real" code uses Carp::croak pretty extensively.

Here's an example.

sub CvsDirEntry::self_test {
    my $de0 = CvsDirEntry->new(NAME => 'slug');
    die unless $de0->name eq 'slug';
    die unless $de0->path eq 'slug';

my $de1 = CvsDirEntry->new(NAME => 'grub'); $de1->set_parent(bless $de0, 'CvsDir'); die unless $de1->name eq 'grub'; die unless $de1->path eq 'slug/grub'; }

I'm not consistently writing the tests first (Wiki:CodeUnitTestFirst), but I'll get there...

eXtreme Programming and Windows

It seems like the vast majority of XP practitioners are Windows sharecroppers. Why is the intersection of XP and open source so small?


Apache is down again in this month's Netcraft survey. What gives?

Comp. Sci. vs. Just Programming:

I must be just a programmer. My only contribution to computer science is the deep thought implementation.


Talked to kfogel and Ben Sussman yesterday on the phone for over an hour. Seemed like nice guys. We concluded that I could make myself useful by writing the CVS to SVN conversion tool. (No comp. sci. there! (-: )

Made my first contribution to subversion tonight. Nothing significant, just some cleanup. I hope it's appreciated.

I'm going on vacation Thursday through next Friday. I'm going to spend the time hacking, because I never get to hack at work. (It's what they pay me for, but they'd rather have me sit in meetings and organize crap.)


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