Freitag, Juni 23, 2006

Fun with testing

I will not talk about the need for unit tests. This I would say is common sense for a modern thinking developer. I recently had to do some small changes in a project. The main developer had already left the company and I got a brief introduction. They all felt very secure because there was a testcase for every single usecase, and also for every possible error. But these were integrationtests, they wrote something into a database, sent requests per URL and parsed the result with httpunit.
So far so good, everyone was happy, but me. Why that? Of course because there were no unit tests at all. It took me about three days to get the tests running. They used real services instead of mocks, so the tests ran just on a dedicated machine, because of firewall restrictions. The logs where analysed to ensure proper behaviour, but because they where running on an external machine, there where some shell scripts to pipe the logs to a socket. I played around for a while, even tried to use logj4 SocketAppender but failed to get the whole thing running. God knows why. So I dropped that validation. The script to run the tests swallowed every exception. The tests were running about 30 minutes, so after reading the latest news you just saw that some of the tests failed but had no glue why.

That all pissed me of, so I started writing unit tests and mock objects. One of my first tests failed and I was wondering why. I discovered a bug where two flags from an external database had been read in the wrong order. You have to know these where not just two flags nobody cared. These had been two of five values these app was evaluating, one of the reasons why these service was written. To evaluate these and to redirect the user depending on the combination of these.

WTF?! But what about the integration tests? At least they ran without an error. So after looking at the testcode, I couldnt believe my eyes: the good old boy was reversing his error and exchanged the flags at initialization time, so everything was looking fine again. I can imagine the situation, maybe he was wondering why his tests failed and thought, oh i might have exchanged the flags. So after reversing them he got the green bar.

This app was in production state for about one year and everyone was happy, but me .....

Keine Kommentare: