Re: Why think unit tests should be in their own source code hierarchy instead of side-by-side

[Tony via Digitalmars-d-announce]

I think unittest blocks are good for write-once and 
quick-and-dirty projects, or as a first-cut of testing that 
ultimately gets moved to a full-grown test suite in a separate 
project. I'd prefer not to read source code that has unittest 
blocks inter-mixed with the actual code.