Do those test really need to read from/write to a file then?
Those 10 test do have to run in separate executables for reasons stated above.
Using a stringstream would save me the hassle of deleting hundreds of temporary files regularly.
This is a separate issue. This would apply to all the other tests. I believe that the temporary file is only left if in fact the test fails - otherwise it is deleted. I have found that stringstream doesn't generally handle code_cvt facets and locales as I would expect. In my limiited testing with them it seemed to just ignore locale issues. I don't know if this is peculiar to the the library implementation I was using or if its a universal thing. Anyway - My confidence in using stringstream for testing was shaken and I invested effort in deleting temporary files. Robert Ramey