datalad fusefs - make its call also "coverage" covered

[yarikoptic]

While reviewing #10 now with the coverage annotation, I wondered if we could make that call run also under coverage. E.g. following similar (if not the same) setup we have in DataLad core -- we augment PATH to point to https://github.com/datalad/datalad/tree/master/tools/coverage-bin so that datalad invocation would use python -m coverage run and then we join all coverage reports before submission: https://github.com/datalad/datalad/blob/master/.travis.yml#L251

[jwodder]

@yarikoptic When I try to run datalad with -m (even just python3 -m datalad create --help, though python3 -m datalad works), I get:

The DataLad AutomagicIO functionality has been moved to an extension package. Please install the Python package `datalad_deprecated` to be able to use it.

And then after I install datalad_deprecated, running python3 -m datalad create --help fails with:

[ERROR  ] Cannot run file 'create' because: [Errno 2] No such file or directory: 'create'

Running datalad without python3 -m still works, though.

[jwodder]

@yarikoptic Looking at the code, it seems that datalad.__main__ runs a Python script instead of being equivalent to the datalad command. Why?

[yarikoptic]

don't use python -m datalad -- that is the "AutomagicIO" mode which is now in datalad-deprecated. The idea is to use python -m coverage run `which datalad` ...

[jwodder]

@yarikoptic I think both Datalad and fuse may be messing with the coverage somehow. I couldn't get fuse_.py or the command in __init__.py to show as covered, and when I added a trivial __main__.py that duplicated the datalad fusefs command, I was able to get that covered but not fuse_.py.

[yarikoptic]

interesting... and that is in foreground mode?

[jwodder]

@yarikoptic Yes, it's in foreground mode.