[Code Friday] Tasty, tasty behaviour-driven development

[maradydd]

By way of sfllaw, a development paradigm I had not previously known about, and tool for developing in this fashion. Holy shmoley. I agree with Bill Tozier, I want this for Python yesterday.

Behaviour-driven development is basically test-driven development on steroids: it takes the principle we like to cite, "write your man pages first!", and hooks it right into the test-driven development cycle, except now you're developing one behaviour at a time, so you can write your tests piece by piece and have individual chunks of the system piece by piece. I like TDD, but sometimes I have to write code fast (and yes, TDD always ends up saving me time in the end, but we've all had those projects where OMG EVERYTHING IS ON FIRE AND THERE'S NOT TIME TO DO IT RIGHT. Behaviour-driven development eliminates your excuses to not do it right: you're producing code as discrete functional units, complete with tests to prove that they are correctly functioning functional units, and you're producing it fast enough to keep management/the client happy. (Clients are sometimes not happy when the first week of work goes into building the unit test suite. Yes, yes, I know, that week of work saves a month or more later on down the line. Some of my clients are no longer my clients for a reason.)

Behaviour-driven development is also a great tool for the "design the UI first" school of programming, and any project that doesn't follow that school of programming is doing it wrong. (Think of it this way: if you're writing a library, design the API first -- that is to say, write the man page first. If you're writing a web application, mock up the user interface, figure out what the damn thing's going to look like and do all your changing-your-mind about how the UI is going to behave before you start laying down AJAX requests.)

Also courtesy sfllaw, a talk by Ben Mabey explaining not only these ideas but the business decisions which motivate behaviour-driven development. This is a really great overview and I strongly encourage any programmer with a pragmatic spirit -- or, even better, an entrepreneurial one -- to block out half an hour of your time to watch it.

Alas and alack, Cucumber is not available for Python yet, and from what I've seen, I really like the way it works. It apparently can be used with PHP, but I really would prefer to avoid PHP if at all possible; my preferred style is just way too functional these days to blend well with PHP. (I've developed a thing for continuation-passing style in the last month or so.) This may end up being the thing that finally motivates me to learn Ruby. I have a little side project going on right now that has a web-application-framework-shaped hole in it, and I had been planning on using Django, but given that it's going to be a Javascript-heavy front end with likely a healthy dose of script.aculo.us, Rails could be a better tool for the job. I'll need to decide if I like how Rails talks to databases; I'm madly in love with the way Django does it and anything less will be a major disappointment, so this is definitely a factor to consider. (Current Rails devs, your input is welcome -- I know very little about your framework. I used to be cranky about the lack of integration with Apache, but there's mod_rails these days and I assume that removes a lot of the reasons I had for bitching.)

And I'd have real continuations. That's always a plus.

Decisions, decisions. But I do like the fact that tools like this exist at all; it's me who needs to get over my uncanny-valley problem with Ruby.

(karnythia, thewayoftheid, tanyad, I'm not talking about the project I'm doing for y'all, this is a different project. So many irons in the fire!)

Comments

[sfllaw.livejournal.com]

I am very happy with the way Django makes RESTful APIs easy. As such, it is JavaScript-friendly, whether you use a library or not.

We use JQuery and have lots of success.

[maradydd.livejournal.com]

Oh, yes. I particularly mention Rails and script.aculo.us because, rik has informed me, the two are integrated about as well as Django and $your_database are. I'm down with programmatic control over dynamically generated user interface elements (which this project will involve). When the user is creating state that the server should have the ability to know about, that's a decent enough reason.

[sfllaw.livejournal.com]

Rails and script.aculo.us are integrated quite well, far better than what Django gives you.

But then again, I suppose it's a differing philosophy thing: http://lethain.com/entry/2008/sep/21/intro-to-unintrusive-javascript-with-django/

[maradydd.livejournal.com]

Hurr. This particular application may be so rich-GUI that it might not be possible to implement a Javascript-free version, much as good standards adherence shakes its fist at me. (I'll be happy to discuss it over IM if you want to hear more, or perhaps help me brainstorm ways to be nice to them what hates Javascript.) But the article is thought-provoking, and I will meditate on it as I turn our mockup into CSS/HTML.

[digitalsidhe.livejournal.com]

FWIW: Rails also makes RESTful APIs very easy. (And Prototype goes along with that, in the way it handles AJAX request returns.)

While Rails is very well integrated with Rails, they're not very tightly integrated. I was worried about that, but it turns out it's pretty easy to use other JavaScript frameworks with Rails; Rails doesn't give you any crap if you just drop in MooTools or jQuery instead.

(Plus, of course, jQuery does a bang-up job of cooperating with other JS frameworks. I was pretty impressed when I saw how easy it is to use jQuery alongside anything else.)

[maradydd.livejournal.com]

Oh, hey, that's good to know, since MooTools might actually be a better hammer for this job. (I am saying this based on having developed a UI in script.aculo.us, and having played with UIs that other people have developed in MooTools; I will have to have a look at the docs.)