Thursday, 16 December 2010

Teaching programming

The world need more and better programmers. Jason Gorman recently wrote this post encouraging people to start offering software apprenticeships, as an alternative to computer science degrees.

He writes:

"our computing education in [the UK] is preparing students for a career in a version of computing most of us don't recognise. Students devote the majority of their time learning theory and skills that they almost certainly won't be applying when they get their first proper job. Computing schools are hopelessly out of touch with the reality of computing in the real world. While employers clamour for TDD or refactoring skills, academics turn their noses up at them and focus on things like formal specification and executable UML and compiler design, along with outdated and thoroughly discredited "software engineering" processes." -- Jason Gorman

Jason ends his post with a call to arms - if you're a good software developer, get yourself an apprentice, and start training them. It's the same message I heard from Dave Hoover when he visited Göteborg recently. I think he also sees a multi-year apprenticeship as a better alternative for training programmers than a computer science degree.

I also recently came across this article, written by a computer science teacher in the US, with the following paragraph:

"I no longer teach programming by teaching the features of the language and asking the students for original compositions in the language. Instead I give them programs that work and ask them to change their behavior. I give them programs that do not work and ask them to repair them. I give them programs and ask them to decompose them. I give them executables and ask them for source, un-commented source and ask for the comments, description, or specification. I let them learn the language the same way that they learned their first language. All tools, tactics and strategies are legitimate. " -- William Hugh Murray

So clearly some academics are teaching in creative ways. Rather than abandoning computer science degrees, might it not be better to improve their content?

One of the things about the XP conference is that it brings together industry and academics, and lets them hear from one another. How to teach programming is a very important topic that is often discussed there. XP2005 for example was held at Sheffield university, where I remember chatting to one of the professors, and being impressed by the way they used eXtreme Programming as part of their undergraduate course.

Another thing that happened at XP2005 was the first coding dojo I attended, and I believe the first one ever held outside of France. It was presented by Laurent Bossavit and Emmanuel Gaillot, founders of the Paris dojo. I was excited to discover a context in which I could improve my practical programming skills, in regular short bursts, alongside a continuing paid job.

So one of the things I do in my new life as an agile testing consultant is to use the coding dojo format to teach people how to program better. We'll do code kata exercises and practice Test Driven Development, Refactoring, and discuss what Clean Code looks like. So far the reaction from professionals I've done this with has been very positive. Lots of people who have been coding for years appreciate the chance to learn new practical skills.

I'm also getting involved in more formal education, this spring I'm teaching a three week course in automated testing, as part of a "Kvalificerad Yyrkesutbildning" in software testing. This is a one year full time course for students wanting to learn a practical skill, as an alternative to going to university and studying a more academic subject. In Sweden you can get a student loan while you're studying this course, and part of the time is spent working in a company gaining on-the-job experience.

I'm starting to plan how I'm going to teach TDD, BDD, and how to use tools like Selenium, Fitnesse, TextTest and Cucumber. I think it's going to be very hands on and practical, but also go into the general principles behind tool choice and writing maintainable automated tests. I'm helping to write a formal syllabus and exam, with criteria for grades awarded.

I guess what I'm trying to say is that I don't like this strand of thought in the Software Craftsmanship movement that wants to abandon formal education. There are lots of ways to train software developers, and apprenticeship isn't without its problems.

I think this is just the sort of thing we'll be discussing at XP2011, where there will be a host of academics and experts from industry. Won't you join us?

Thursday, 9 December 2010


I've just been appointed to the role of Industry Programme Chair for XP2011, which will be held in Madrid in May. I've been to 7 of the previous 11 XP conferences and I am so pleased to be asked to contribute to the success of the conference this year by doing this role.

Rachel Davies is the general chair, and I am really looking forward to working with her and the other organizers. Rachel is one of those people I have met repeatedly at conferences and always has something interesting to contribute. More recently, I read her excellent book on Agile Coaching. I can't remember exactly when I first met her, but I do remember meeting her former colleagues from Connextra, Tim MacKinnon and Steve Freeman. I can still picture them in the small minibus that picked us up from a tiny Italian airport in 2002. It was a hot summers day, and we were driven at high speed along small Sardinian roads to the lovely hotel Calabona by the sea and the historic walled city of Alghero. I remember being so impressed to meet some people who were actually doing eXtreme Programming for real.

There were so many inspirational people at that conference, it was really a turning point in my career. I just found the old conference programme online here, and it brings back so many memories!

I remember sitting by the pool discussing subjects like how to test drive refactoring with Frank Westphal and Steve Freeman. There was a firey keynote from Ken Schwaber encouraging us to start a revolution in software development world. I remember Joshua Kerievsky asking Jutta Eckstein to explain all about how she was doing XP with a team of over 100 people. Following David Parnas' keynote about using a formal test specification language to define requirements I remember Martin Fowler opining about its usefulness or lack of it, (do read his blog post about it).

The colourful personality of Scott Ambler demonstrated his ability to break a plank of wood in two with his bare hands, as some kind of lesson to do with dedication and focus. The conference dinner at Poco Loco really was a little crazy, with a bunch of uncoordinated geeks going for it on the dancefloor while the local band played very loudly. The morning after everyone was rather subdued when listening to Enrico Zaninotto reading his keynote in halting English, relating XP to the history of manufacturing and modern lean ideals. Half the audience was having trouble staying awake which in no way reflected the quality of what he was saying. It was truly inspiring, and Mary and Tom Poppendieck in particular were listening in rapt attention.

Michael Feathers wore a T-shirt saying "Save the LSF", and Geoff and I asked him why he was so interested in platform computing's Load Sharing Facility. It turned out Alan Francis had recently become unemployed and Mike was helping in the campaign to "Save the Lightly Scottish Fellow"!

Laurent Bossavit was going round trying to attract people to his Birds Of a Feather session on the writings of Gerald Weinberger. Erik Lundh was taking about his team in Sweden who had done a complete XP iteration in 2 days when faced with an unexpected deadline. Steven Fraser seemed to be videoing everything and anything, including someone demonstrating the correct way to twirl Italian Spaghetti on a fork. Mike Hill was (as ever) being loud but friendly. Charlie Poole seemed to be full of insightful analogies and comments. Dave Hussman was really friendly too.

It was just fantastic the way the XP community welcomed us in, and particularly Kent Beck's attitude was instrumental in that. My husband Geoff and I presented a poster at the conference with title "One suite of automated tests" based mainly on Geoff's experiences with the tool that was to become TextTest. We turned up on the first day for a workshop about "testing in XP", and Geoff was immediately controversial by saying that he didn't do any unit testing, only this weird text-based testing thing using log comparison. He said he found it so successful that he used it instead of both the XP practices of functional and unit testing. I remember several people being quite dismissive of his ideas.

Later in the conference, Kent Beck made a particular effort to talk to us and we took our picture standing by our poster. Apparently he had been asking people to try to be inclusive and friendly to us after the somewhat negative reaction to our ideas. I think he wanted the newly-forming XP community to be welcoming and to embrace diversity of opinion.

So now I should turn this around and look instead to the future. I'd love it if even half the people I've mentioned in this post found time in their diaries to come to Madrid in May for XP2011. I wouldn't want them to come alone though, there are so many fantastic and inspirational people who have joined the ever-expanding agile community since 2002.

I am every bit as keen now as Kent was then to see that the agile community embraces newcomers, and that the XP conference should provide a space where researchers and practitioners can freely discuss the state of the art. I hope we'll make new friends and business contacts, learn loads, and have fun. Would you like to join us there?

Friday, 3 December 2010


Last night at GothPy we had a play with Django, a web application framework for Python. I'm fairly familiar with Rails, so it was interesting to see a different take on solving the same kinds of problems.

I downloaded Django for the first time when preparing for the meeting, and spent about a day going through the tutorial and trying stuff out. At the meeting were a few people who have used Django before, notably Mikko Hellsing, who has worked with it daily for several years.

It was so much easier learning the tool from people who knew it than by reading the documentation. Constant code review and real time answering of questions is just brilliant for learning.

At the meeting we decided to implement a very very simple web application, similar to the one that Johannes Brodwall performed as a Kata at XP2010 together with Ivar Nilsen. He calls it "Java EE Spike Kata" since he does it in Java with no particular web frameworks, just what comes with Java. (There is a video of him doing it on his blog, and sample solution here on github).

I thought we should be able to implement the same little application in any web framework, and it might be interesting to see differences, so I though we should try doing it in Django. It just involves two pages. One page "Add User" which lets you create a new user and save it to the database, and another page "Search User" which lets you search for users, and presents results. So the scenario is to create a user, search for them, and see they are returned.

When I work on a problem in Rails I usually start with a Cucumber scenario for the feature, and I discovered there is a python version of Cucumber called Lettuce. We could have course have just used Cucumber with python, but given the big "WARNING - Experimental" notice Aslak wrote on this page, I thought we could give Lettuce a try.

So at the meeting we all worked together with one laptop and a projector, (me at the keyboard), and we started with a Lettuce scenario. We implemented step definitions using Django's test Client, which is a kind of headless browser that understands how to instrument a Django application. Then we spent a couple of hours writing Django code together until the scenario was all green.

The code we ended up with isn't much to write home about, but I've put it up on github here.

What we learned from this exercise
Of course since I know Rails much better, I found it interesting to compare the two web frameworks. Django seems similar in many ways. It was dead easy to get up and running, it gives you a basic structure for your code, and separates the model from the presentation layer.

The O-R mapping looks quite similar to ActiveRecord in the way you declare model classes backed by tables in the db. The presentation layer seems to have a different philosophy from Rails though. The html view part is rather loosely coupled to your application, and doesn't allow you to embed real python code in it, just basic control structures.

You hook up the html to the controller code using url regular expression matching. I was a little confused about exactly how was supposed to work, since what I considered controller code was put in a file called "". Most of the code we wrote ended up in here, and I feel a bit unhappy with it. It seems to be a mixture of stuff at all levels of abstraction. The Django Form objects we used seemed quite powerful though, and reduced the amount of code we had to write.

The biggest difference I noticed compared with Rails was how explicit Python is about where stuff comes from. You always have to declaratively import or pass stuff before you can use it, so I found it straightforward to follow the connections and work out which code was executed and where it came from. I think that is because of Python's philosophy of strict namespaces, which Ruby doesn't have so much of.

I also liked the way Django encourages you to structure a larger web application into a lot of independent smaller ones, and lets you include and re-use other people's small apps. Rails has plugins too of course, but I thought Django's way made it seem very natural to contribute and re-use code.

Comparing Lettuce to Cucumber, they look almost the same, (by design). One small difference I found was that Cucumber step definitions don't care if you write "Given", "When" or "Then" in front of them, whereas Lettuce did. So I had steps like this:

Then I should see "results found"
And I should see "Name"

where the first step passed and the second step was reported as unimplemented by Lettuce. So Lettuce need a little more work to be really usable.

I was also pretty disappointed by the Django test client for implementing test steps. It seemed to interact with pages at an abstraction layer lower than I am used to - at the level of making post and get requests and parsing html as a dom. I missed Capybara and its DSL for interacting with web pages. I couldn't find any equivalent. I probably should have turned to Selenium directly, but since we had no client side javascript it seemed overkill. (Francisco Souza has written about using Lettuce with Selenium compared with the Django test client here).

When it comes to unit-level testing, Django provides an extension to the normal unittest tool that comes with python (unittest was originally based on JUnit). We didn't do much with it at the session, and it seemed to work fine. It's nothing like RSpec though, and I miss that expressiveness and structure for my tests whenever I work in Python.

All in all it was fun to look at Django with a group and to get some really helpful comments and insights from people who know it far better than I do. The Kata we chose seemed to work ok, but I should really do it again in Rails since I spent the whole time comparing Django with Rails in my head, not Django with Johannes' Java code :-)

My conclusions are basically that Django looks like a good alternative to Rails. It would take time to learn, and surely has strengths and weaknesses I can't really evaluate from one short session looking at it. However, I'd fairly sure I'd have to do some work improving the testing tools if I was going to be happy working with it for real.