Testing an API which require Windows to generate input files

[Conor McCarthy]

Wine-Bug: https://bugs.winehq.org/show_bug.cgi?id=12501

I've implemented some of the functions in mspatcha.dll, including
ApplyPatchToFileW. I'm currently writing tests, but patch creation is not
implemented, so only Windows can generate patch test files. How does
testing normally work in this situation? It is possible to embed some very
small test files as strings within the source code. A crosstest build
should work too. Any other suggestions? I am not yet very familiar with the
code base.

Regards,
Conor