[rspec-users] Mocking expectations on I/O operations

[Ash Moran]

On 15 Sep 2011, at 10:05, Rob Aldred wrote:

> Thanks Justin,
> That isnt working... its erroring with:
> 
> The method `delete` was not stubbed or was already unstubbed

Hi Rob

For reasons I could go into, when I'm coding myself I don't usually stub  out file system access or other third party systems. Rather, I write an adapter that behaves in the way I expect and test it using the real file system, then test the rest of the system against a mock. That avoids this category of problem.

What you're doing here appears to be mixing both real (from mini_magick) and stubbed (your own library's) calls to filesystem code, and I think it's the asymmetry that's biting you.

I could explain the above in more detail*, but in lieu of that, here's another angle: can you run the code in a subdirectory per image and nuke that after? That way you only have one point to hit for the cleanup.

HTH

Ash

* As a quick example, you might have a TempFileCleaner object in place of IconGenerator#cleanup, seeded with all the potential temp filenames, or some algorithm to figure them out

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