February 15, 2010

...Learn TDD with Codemanship

Wheel-driven Reinvention

One aspect of software development which is at once both amusing and troubling is the ability of us young whippersnappers to completely ignore what's gone before and reinvent established wisdom in our own image - often stealing the credit.

Take testing as an example. What do we know about testing software today that we didn't know, say, thirty years ago? Sure, we have new tools and testing has to fit within new approaches to the process of writing software as a whole, but fundamentally what have we discovered in the last decade or so?

Testing behaviour still works, by necessity, much as it has always worked by necessity. We must put the system under test in some desired initial state, then we must provide some stimulus to the system to trigger the behaviour we wish to test, then we must make observations about the final state of the system or about any behaviours that should have been invoked (e.g., a remote procedure call or a database request) in response to the combination of our stimulus and the initial conditions. And this process must be repeatable and predictable, like any good scientific test.

Though the culture of testing software may have evolved, much of it for the better, and the technology may have improved (though that is questionable), and though there are undoubtedly more people testing their systems today, when it comes to the business of writing and executing tests, there's really nothing new under the sun.

The same is true of many aspects of contemporary software development. Like it or nay, iterative and incremental development is older than C. We just weren't doing it back then, in the main.

Indeed, pick any "new" aspect of development and trace it back to its roots, and we discover that most novelties are actually much older than many of us thought. Objects are an invention from the sixties. Use cases hail from the seventies. Responsibility-driven design was being practiced before Frankie told us to Relax. UML existed in a fragmentary form before the Berlin Wall came down. People were writing code to satisfy tests back when those tests were stored on magnetic tape. Indeed, some of the descriptions of programming that was done for the very first computers rings bells with those of us who practice that black art today.

Younger developers like me, though, seem to readily believe that our time around is the first time around and feel no compunction to educate ourselves about the achievements of "old-timers", preferring instead to invent things anew - with sexier names and shinier tools, admittedly.

Our desire to reinvent goes as far as redefining words that already have a well-established definition. "Agile" no longer means "nimble" , "quick" or "spry". Today it apparantly means "communication, feedback, simplicity and courage". Or "iterative and incremental". Or "evolutionary". Or "Scrum-Certified". I caught someone the other day proferring their definition of "testable", which apparantly now requires us to go through "public interfaces". This is bad news for many scientists, who must now rewrite their peer-reviewed papers to incorporate the appropriate programming language with which to express the "testability" of their theories.

If software development was physics, we might expect newcomers to work through and understand the current body of knowledge before they start adding to it. That way, at the very least, we could avoid a great deal of duplication of effort. We may also avoid the tendency of our industry to throw "old-timers" on the scrapheap just because, even though they are probably just as current in their practical ability to deliver working software, they're not "down with the kids" on all the latest street slang for concepts that have been kicking around the block for decades.

The thinking of our elders and betters is far from irrelevent and outmoded. We can still learn a thing or two from the likes of Jacobson, Knuth and Hoare, should we choose to reject fashion in favour of substance in the approach we take to our work.
Posted 8 years, 3 months ago on February 15, 2010