I personally see that as a unit test; Plenty of unit tests use real files on the filesystem in their mocks, you're hermetically sealed from the rest of the syst

I personally see that as a unit test; Plenty of unit tests use real files on the filesystem in their mocks, you're hermetically sealed from the rest of the system, how is it not a unit test? I'm just arguing vocabulary, though. There seems to be a spectrum, pure unit tests on one side, then integration tests, with Canaries way off to the other side.