Sunday, March 23, 2008

It's official - I'm a Python hacker!

Lately, it hasn't been building the application that's captured my imagination so much as figuring out a way to validate the correctness of the application. When you're dealing with a sprawling behemoth of an application of varying levels of quality (this isn't a dig at co-workers - I've got more than my share of turds baked in there) that's so absurdly data-driven that... well. I've come to grips with the fact that chunk by chunk, we've built a borderline unmanageable enterprise application.

There's blocks of the application that I'm flat-out scared to touch because of their fragility. There's a reason that Jenga never took off as an application platform.

There's so many tables (I'll ballpark it at 300, but it could be more than that) that I have to walk through stored procedures and table definitions to figure out why many of them exist. Thankfully, at least they're well-normalized even if, again, some are really, really arcane.

More interesting to me than anything else lately is testing the application. When it comes to a giant database-driven web application, there are no easy answers to "how do you prove it is working correctly?". Well, at least none that The Google is willing to impart on me.

As I've mentioned before and will be talking about again soon (I'm busy hacking, d00dz!), I heart the hell out of Watir. You run WatirMaker, you walk through your application, you're 80% or more of your way to a test case. But... it runs slow. It takes over 3 hours to run 130-ish test cases of varying complexity on the old desktop I snuck the regression automation environment on to. I love it, but I worry about its scalability.

Over on programming.reddit, I saw a new tool announced that tickled me in all the right spots - Pylot. It was designed as a web load-testing tool (I've seen the QA folks at work use Quick Test Pro, but it's a fragile piece of shit if I've ever seen (and built) one) and has lightweight validation features built into it. On that end, it's not as fully-featured as Watir (I've updated WatirMaker to do 31337 things like generate automagic tests when you click on text in table cells/spans/the body) but... speed! Free replacement for Quick Test Pro (maybe)!

I saw it and immediately got to wondering about writing tests for it - is there anything that will get me 80% there? Not yet. Could I take WatirMaker and update it so that it emits Pylot-friendly XML? Sure, but doesn't that feel just a lot unholy?

So I downloaded Python and got to work doing the crappiest, stripped-down-est translation of a useful Ruby meta-script to Python that you've ever seen. A few hours of grunting and banging my head later, I've got something to show for it, thanks in part to the duders over in #python on EFNet.

Does anyone have any experience working with buffer objects? I'm getting one handed back to me and I'm completely lost as to how to coax it back to a string.

um, str(yourbuffer)

that's what makes python so difficult to pick up -- its simplicity

If I were them, I'd clown on me too. In my defense, The Google wasn't all that helpful when it came to working with buffers in Python and I'm a complete new jack and calling yourbuffer.tostring() wasn't getting me anywhere useful and enough ball-aching.

So here's my first stab at It requires the Win32 extensions for Python to run and you run it the same way as WatirMaker - pop open a command prompt and " > test.xml", browse around the Internet Explorer window that opens up, close IE when you're done and test.xml is set up for you. Minus tests.

Did I really spend 5 hours knocking out 44 lines of Python instead of playing Team Fortress 2? There's something way wrong with me.

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