Oil And Water, Or Are They?

Tester and developer couldn't be further apart, both of them fighting all the time without knowing any better. As one of our former tester put it, we have different goals: developers want the software to work, testers want it to break. For a long and regrettable time we shared this belief. But then we thought with agile it is over: bringing the tester closer to the team, both locationally and spiritually, would bring everyone to the same goal, i.e. to create quality software. It didn't work out as expected. Maybe the shared goal still wasn't shared enough, but I think we were missing a more important ingredient.
Fortunately we had learned our lesson, and with our new tester we tried harder. Once again Kent Beck helped us to find the missing pieces: Respect and Trust.

Though in his lecture he talks specifically about how trusty realtionship between developers and clients can help both parties to concentrate on creating values, I watched the inner workings of respect and trust in a tester-developer relationship.
In a timespan of a couple of 2-week iterations, our tester became a full-member of our team, thank to trust and respect. Quite rapidly we have arrived to the point where she trusts the developers enough to dare to ask them about the observed and expected behaviour of the system. She knows now she can be sure that a bug-candidate won't be dismissed due to programmers' arrogance or ego. She also knows she can freely ask all sorts of questions and won't be shushed or ignored or made fun of.
On the other hand we developers learned to respect her and her view on our software, and we learned not to discount whatever she has to say based solely on the fact that she didn't write the code, and in fact wouldn't even know how to.
Few minor, though important things at last. This productive relationship couldn't spring to life without our seriousness toward bugs: in an attempt to avoid the mini-waterfall effect we try to act quickly upon new bugs, this is not only practical from the technical point of view but also expresses respect, and thus strengthen trust. Unit and functional tests makes it possible that very few already working features break due to a fix of a new bug, again strengthening trust. Finally, our relatively fast build closes a very short feedback-loop of finding, fixing and retesting a bug creating a productive and positive atmosphere.