October 9, 2008

Learning and Understanding

I've just read this sample chapter from Andy Hunt's new book: Pragmatic Thinking and Learning: Refactor Your "Wetware", that deals with the Dreyfus model of skill acquisition. While this kind of introspection is probably more the domain of Michael (the Braidy Tester) Hunter's blog, I found it fascinating.
In particular it explained two things for me:

  1. That Agile Projects really do need those really skilled practioners driving them in order to succeed. These are the Jedi Masters that just "feel the force" rather than "read the manual".
  2. That a lot of the anxiety I feel when learning something new comes from that fact that I don't yet have that fully-formed picture of the conceptual framework. I can almost feel that discomfort lessen each time I get one of those "a-ha" moments. Which interestingly occur not when something I'm trying works, but rather, when I understand why all the previous attempts didn't.

I feel that this second point is important for testers to tune into - the better your internal model of the business/ techological processes, the less likely you are to miss important bugs in business/technological logic.

I'm sure others will relate to this idea, let me know if you "feel it" too. Anyway I can't wait to digest the rest of the book.

October 7, 2008

Visual Studio Web Tests - Random Access is not quite Random

I've just been grappling with an issue in VS2008 Tester Edition that was skewing the load profile I'm after for my latest performance test assignment.

In a WebTest (either coded or UI-friendly) if you set "Random" access on Data Source and set the Number of Test Runs to a "Fixed Run count", the test runner will randomly select from all but the last row of data.
It works fine for 1 row, but with 2 or more rows, it will always ignore the last row. There is an n-1 bug in there somewhere....I've reported it to MS via the forums.

I've checked and VS2005 seems to have the same issue, and it affects at least csv and xml data source types.

The workaround is easy, as all you need is a padding row, but if you're wondering why the maths is off when using random access, this might be why.