On 21/12/14 09:21, Albert-Jan Roskam wrote:
Don't postpone writing unittests (don't use doctest).
But do wait till you know what you will be testing. You can't write a unit test until you have a unit in mind. The OP seems to be struggling to figure out what units he needs. Once he has done that, unit testing can be included as part of the normal discipline of writing code. But you need to know the structure before you get to that stage. But even with system testing the first challenge is still to understand what it is you are trying to build. Until you understand the problem you can't deliver a solution nor can you test if the solution is correct.
They really give you focus and confidence (peace of mind!).
Often misplaced! Remember that unit tests only test units, you also need system tests and very few unit testing frameworks are any good at that. And especially where GUI front ends are used. There are UI testing frameworks and they help, but the real challenges in testing any system are the test data build and the timing and synchronising of the tests. Of course, system testing should never, ideally, be done by the programmers who wrote the code, but "ideally" often isn't possible...
If you also use version control, you can automatically
> run all tests before each commit. In theory yes, but if it's a big system that may not be practical. retesting 10,000+ files takes a long time even on modern computers. Now I doubt if many readers of this list are working on 10000 file codebases but you need to bear in mind that some day you may be and these *rules* don't always apply. I've worked on systems where running a full build/test cycle took 3 to 4 days. It was usually done over the weekend and Mondays and Tuesdays were reserved for bug fixing. The aim being to have a new working system every Wednesday morning. -- Alan G Author of the Learn to Program web site http://www.alan-g.me.uk/ http://www.amazon.com/author/alan_gauld Follow my photo-blog on Flickr at: http://www.flickr.com/photos/alangauldphotos _______________________________________________ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
