[rspec-users] testing behaviour or testing code?

[Peter Marklund]

> There's a very useful guideline in TDD that says "test YOUR code, not
> everyone elses." The validation library we're testing here is
> ActiveRecord's. It's already tested (we hope!).

Personally, I don't have the courage to assume Rails code is always  
working. I know from experience it doesn't always work although it is  
quite solid in general. The Rails code has been tested but not in  
conjunction with my particular apps. I also want to test my  
assumptions of how the Rails API works, maybe it doesn't work as I  
think. Having tests/specs that cover Rails interaction with my app,  
which higher level tests of course naturally do (system/integration  
tests), gives me much more courage to upgrade Rails as well.

Peter