July 31, 2014
My Top 5 Most Under-used Dev PracticesSo, due to a last-minute change of plans, I have some time today to fill. I thought I'd spend it writing about those software development practices that come highly recommended by some, but - for whatever reason - almost no teams do.
Let's count down.
5. Mutation Testing - TDD advocates like me always extol the benefits of having a comprehensive suiite of tests we can run quickly, so we can get discover if we've broken our code almost immediately.
Mutation testing is a technique that enables us to ask the critical question: if our code was broken, would our tests show it?
We deliberately introduce a programming error - a "mutation" - into a line of code (e.g., turn a + into a -, or > into a <) and then run our tests. If a test fails, we say our test suite has "killed the mutant". We can be more assured that if that particular line of code had an error, our tests would show it. If no tests fail, that potentially highlights an gap in our test suite that we need to fill.
Mutation testing, done well, can bring us to test suites that offer very high assurance - considerably higher than I've seen most teams achieve. And that extra assurance tends to bring us economic benefits in terms of catching more bugs sooner, saving us valuable time later.
So why do so few teams do it? Well, tool support is one issue. The mutation testing tools available today tend to have a significant learning curve. They can be fiddly, and they can throw up false positives, so teams can spend a lot of time chasing ghosts in their test coverage. It takes some getting used to.
In my own experience, though, it's worth working past the pain. The pay-off is often big enough to warrant a learning curve.
So, in summary, reason why nobody does it : LEARNING CURVE.
4. Visualisation - pictures were big in the 90's. Maybe a bit too big. After the excesses of the UML days, when architects roamed the Earth feeding of smaller prey and taking massive steaming dumps on our code, visual modeling has - quite understandably - fallen out of favour. So much so that many teams do almost none at all. "Baby" and "bathwater" spring to mind.
You don't have to use UML, but we find that in collaborative design, which is what we do when we work with customers and work in teams, a picture really does speak a thousand words. I still hold out hope that one day it will be commonplace to see visualisations of software designs, problem domains, user interfaces and all that jazz prominently displayed in the places where development teams work. Today, I mainly just see boards crammed with teeny-weeny itty-bitty index cards and post-it notes, and the occasional wireframe from the UX guy, who more often than not came up with that design without any input at all from the team.
The effect of lack of visualisation on teams can be profound, and is usually manifested in the chaos and confusion of a code base that comprises several architectures and a domain model that duplicates concepts and makes little to no sense. If you say you're doing Domain-driven Design - and many teams do - then where are your shared models?
There's still a lot of mileage in Scott Ambler's "Agile Modeling" book. Building a shared understanding of a complex problem or solution design by sitting around a table and talking, or by staring at a page of code, has proven to be uneffective. Pictures help.
In summary, reason why so few do it: MISPLACED AGILE HUBRIS
3. Model Office - I will often tell people about this mystical practice of creating simulated testing environments for our software that enable us to see how it would perform in real-world scenarios.
NASA's Apollo team definittely understood the benefits of a Model Office. Their lunar module simulator enabled engineers to try out solutions to systemm failures on the ground before recommending them to the imperilled astronauts on Apollo 13. Tom Hanks was especially grateful, but Bill Paxton went on to star in the Thunderbirds movie, so it wasn't all good.
I first heard about them doing a summer stint in my local W H Smith in the book department. Upstairs, they had a couple of fake checkouts and baskets of fake goods with barcodes.
Not only did we train in their simulated checkout, but they also used them to analyse system issues and to plan IT changes, as well as to test those changes in a range of "this could actually happen" scenarios.
A Model Office is a potentially very powerful tool for understanding problems, for planning solutions and for testing them - way more meaningful than acceptance tests that were agreed among a bunch of people sitting in a room, many of whom have never even seen the working environment in which the software's going to be used, let alone experienced it for themselves.
There really is no substitute for the real thing; but the real thing comes at a cost, and often the real thing is quite busy, actually, thank you very much. I mean, dontcha just hate it when you're at the supermarket and the checkout person is just learning how it all works while you stand in line? And mistakes that get made get made with real customers and real money.
We can buy ourselves time, control and flexibility by recreating the real thing as faithfully as possible, so we can explore it at our leisure.
Time, because we're under no pressure to return the environment to business use, like we would be if it was a real supermarket checkout, or a real lunar module.
Control, because we can deliberately recreate scenarios - even quite rare and outlandish ones - as often as we like, and make it exactly the same, or vary it, as we wish. One of the key reasons I believe many business systems are not very robust is because they haven't been tested in a wide-enough range of possible circumstances. In real life, we might have to wait weeks for a particular scenario to arise.
Flexibility, because in a simulated environment, we can do stuff that might be difficult or dangerous in the real world. We can try out the most extraordinary situations, we can experiment with solutions when the cost of failure is low, and we can explore the problem and possible solutions in ways we just couldn't or wouldn't dare to if real money, or real lives, or real ponies were at stake.
For this reason,, from me, Model Offices come very highly recommended. Which is very probably why nobody uses them.
Reason why nobody does it - NEVER OCCURRED TO THEM
2. Testing by Inspection - This is another of those blind spots teams seem to have about testing. Years of good research have identified reading the code to look for errors as one of the most - if not the most - effective and efficient ways of finding bugs.
Now, a lot of teams do code reviews. It's a ritual humiliation many of us have to go through. But commonly these reviews are about things like coding style, naming conventions, design rules and so forth. It's vanishingly rare to meet a team who get around a computer, check out some code and ask "okay, will this work?"
Testing by inspection is actually quite a straightforward skill, if we want it to be. A practice like guided inspection, for example, simply requires us to pick some interesting test cases, and step through the code, effectively executing it in our heads, asking questions like "what should be true at this point?" and "when might this line of code not work?"
If we want to, we can formalise that process to a very high degree of rigour. But the general pattern is the same; we make assertions about what should be true at key points during the execution of our code, we read the code and dream up interesting test cases that will cause those parts of the code to be executed and ask those questions at the appropriate times. When an inspection throws up interesting test cases that our code doesn't handle, we can codify this knowledge as, say, automated unit tests to ensure that the door is closed to that particular bug permanently.
Do not underestimate the power of testing by inspection. It's very rare to find teams producing high-integrity software who don't do it. (And, yes, I'm saying it's very rare to find teams producing high-integrity software.)
But, possibly because of associations with the likes of NASA, and safety-critical software engineering in general, it has a reputatioon for being "rocket science". It can be, if we choose to go that far. But in most cases, it can be straightforward, utilising things we already know about computer programming. Inspections can be very economical, and can reap considerable rewards. And pretty much anyone who can program can do them. Which is why, of course, almost nobody does.
Reason why nobody does it - NASA-PHOBIA
1. Business Goals - Okay, take a deep breath now. Imminent Rant Alert.
Why do we build software?
There seems to be a disconnect between the motivations of developers and their customers. Customers give us money to build software that hopefully solves their problems. But, let's be honest now, a lot of developers simply could not give two hoots about solving the customer's problems.
Which is why, on the vast majority of software teams, when I ask them what the ultimate business goals of what they're doing are, they just don't know.
Software for the sake of software is where our heads are mostly at. We buiild software to build software.
Given a free reign, what kind of software do developers like to build? Look on Github. What are most personal software projects about?
We don't build software to improve care co-ordination for cancer sufferers. We don't build software to reduce delivery times for bakeries. We don't build software to make it easier to find a hotel room with fast Wi-Fi at 1am in a strange city.
With our own time and resources, when we work on stuff that interests us, we won't solve a problem in the real world. We'll write another Content Management System. Or an MVC framework. Or another testing tool. Or another refactoring plug-in. Or another VCS.
The problems of patients and bakers and weary travelers are of little interest to us, even though - in real life - we can be all of these things ourselves.
So, while we rail at how crappy and poorly thought-out the software we have to use on a daily basis tends to be ("I mean, have they never stayed in a hotel?!"), our lack of interest in understanding and then solving these problems is very much at the root of that.
We can be so busy dreaming up solutions that we fail to see the real problems. The whole way we do development is often a testament to that, when understanding the business problem is an early phase in a project that, really, shouldn't exist until someone's identified the problem and knows at least enough to know it's worth writing some software to address it.
Software projects and products that don't have clearly articulated, testable and realistic goals - beyond the creation of software for its own sake - are almost guaranteed to fail; for the exact same reason that blindly firing arrows in random directions with your eyes closed is almost certainly not going to hit a valuable target. But this is what, in reality, most teams are doing.
We're a solution looking for a problem. Which ultimately makes us a problem. Pretty much anyone worth listening to very, very strongly recommends that software development should have clear and testable business goals. So it goes without saying that almost no teams bother.
Reason why so few teams do it - APATHY
Posted 2 weeks, 4 days ago on July 31, 2014