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This article was originally published in the Summer 2003 issue of Methods & Tools


XP Testing Without XP: Taking Advantage of Agile Testing Practices

Lisa Crispin, http://lisa.crispin.home.att.net

In the rocket-fast late 90s, I struggled with using traditional software process and testing practices on e-commerce applications. Then I read Kent Beck’s Extreme Programming Explained and had an amazing ‘aha’ moment. Ron Jeffries sums it up best:

Extreme Programming is a discipline of software development based on values of simplicity, communication, feedback, and courage. It works by bringing the whole team together in the presence of simple practices, with enough feedback to enable the team to see where they are and to tune the practices to their unique situation. (www.xprogramming.com)

Applying more discipline to traditional waterfall process had not helped my team. A new kind of discipline based on values such as communication, simplicity and feedback might be the answer! I immediately took an opportunity to join an XP team as a tester, and enjoyed working on XP teams for the next 18 months. Indeed, XP did allow us to produce high-quality e-commerce applications on time and on budget! Our customers were happy! We were happy! We struggled some with how I, as tester, could best contribute to the team, as the XP literature at the time didn’t say much on that subject. With the whole team focused on quality and testing, we came up with some great solutions. I was so excited about XP testing that I co-authored a book on it (Testing Extreme Programming, with Tip House).

How XP Testing is Different

I found that XP testing was different in many ways from ‘traditional’ testing. The biggest difference is that on an XP project, the entire development team takes responsibility for quality. This means the whole team is responsible for all testing tasks, including acceptance test automation. When testers and programmers work together, the approaches to test automation can be pretty creative!

As Ron Jeffries says, XP isn’t about ‘roles’, it’s about a tight integration of skills and behaviors. Testing is an integrated activity on an XP team. The development team needs continual feedback, with the customer expressing their needs in terms of tests, and programmers expressing design and code in terms of tests. On an XP team, the tester will play both the customer and programmer ‘roles’. She’ll focus on acceptance testing and work to transfer her testing and quality assurance skills to the rest of the team.

XP Tester Activities

Here are some activities testers perform on XP teams.

  • Negotiate quality with the customer (it’s not YOUR standard of quality, it’s what the customer desires and is willing to pay for!)
  • Clarify stories, flush out hidden assumptions
  • Enable accurate estimates for both programming and testing tasks
  • Make sure the acceptance tests verify the quality specified by the customer
  • Help the team automate tests
  • Help the team produce testable code
  • Form an integral part of the continuous feedback loop that keeps the team on track.

The Nature of XP Testing

The biggest difference between XP projects and most ‘traditional’ software development projects is the concept of test-driven development. With XP, every chunk of code is covered by unit tests, which must all pass all the time. The absence of unit-level and regression bugs means that testers actually get to focus on their job: making sure the code does what the customer wanted. The acceptance tests define the level of quality the customer has specified (and paid for!)

Testers who are new to XP should keep in mind the XP values: communication, simplicity, feedback and courage. Courage may be the most important. As a tester, the idea of writing, automating and executing tests in speedy two or three week iterations, without the benefit of traditional requirements documents, can be daunting.

Testers need courage to let the customers make mistakes and learn from them. They need courage to determine the minimum testing that will prove the successful completion of a story. They need courage to ask their teammates to pair for test automation. They need courage to remind the team that we are all responsible for quality and testing. To bolster this courage, testers on XP teams should remind themselves that an XP tester is never alone – your team is always there to help you!

XP Testing Without an XP Team

After my rewarding, if challenging, experience as a tester on XP teams, the bad economic times caught up with me and I had to take a job back on the "dark side". Oh, my new company was great and they were interested in XP, but they were a tiny shop with a huge job to do and it felt to me like barely controlled chaos. My initial attempts to apply XP practices, such as having daily XP-style stand-ups with my test team, were disasters. I just had to hunker down, hire people that I thought would be able and willing to try agile test practices, and wait for my opportunity.

Things eventually slowed down enough for my team to have time to spike test automation solutions. Many of our applications are written in Tcl. Tcl is a powerful scripting language which can lend itself to test automation, so we taught ourselves Tcl. We needed a way to load bulk data for volume testing, and one of the programmers helped out with a Tcl script; we took over maintenance for it and started expanding its functionality. Some of our test automation could be handled with fairly simple shell scripts. Other automation requirements demanded more robust tools. As we started down our own path of exploring test automation, the programmers started writing automated unit tests.

I learned the hard way that being an advocate for XP or any kind of agile development doesn’t introduce change. Instead, you and your team need to identify what hurts and look at what XP or agile approaches could help heal that pain. By adopting XP-style planning and writing acceptance testing up front, my new development team has started exploring what agile practices might help them.

Let’s look at what agile testing practices might help you, no matter what style of software development process you are using.

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