Unit testing handling of degraded network stack, file corruption, and other imperfections

Question

I\'m primarily a C++ coder, and thus far, have managed without really writing tests for all of my code. I\'ve decided this is a Bad Idea(tm), after adding new features that subt

Answer 1

Sometimes I'll create two (or more) test suites. One suite uses mocks/stubs and only tests the code I'm writing. The other tests test the database, web sites, network devices, other servers, and whatever else is outside of my control.

Those other tests are really tests of my assumptions about the systems my code interacts with. So if they fail, I know my requirements have changed. I can then update my internal tests to reflect whatever new behavior my code needs to have.

The internal tests include tests that simulate various failures of the external systems. Whenever I observe a new kind of failure, either through my other tests or as a result of a bug report, I have a new internal test to write.

Writing tests that model all the bizarre things that happen in the real world can be challenging, but the result is that you really think about all those cases, and produce robust code.