Align accepted filetypes with docstring description

[maxrjones]

The docs state the filetype Can be one of {‘netCDF3’, ‘netCDF4’, ‘HDF’, ‘TIFF’, ‘GRIB’, ‘FITS’, ‘dmrpp’, ‘zarr_v3’, ‘kerchunk’}" but in reality few of these arguments actually worked due to case sensitivity.

[TomNicholas]

Thanks! Is the string type tested explicitly anywhere?

In general this function signature is a little messy, especially as we have file types and backends. I think once we generalise this into an entry point we should clean it up.

[TomNicholas]

Also TIFF and GRIB don't currently work

[maxrjones]

Also TIFF and GRIB don't currently work

TIFF doesn't even work for Kerchunk-backed virtualization?

Edit, nevermind forgot about #291 😓

[maxrjones]

Thanks! Is the string type tested explicitly anywhere?

String type is tested, but a non-string and non-FileType type isn't. I'm working on getting to 100% code coverage for this section now (apologies for not thinking to put this as a draft first)

[codecov]

Codecov Report

Attention: Patch coverage is 50.00000% with 4 lines in your changes missing coverage. Please review.

Project coverage is 79.80%. Comparing base (fcdd5e4) to head (da8aac4).
Report is 7 commits behind head on main.

Files with missing lines	Patch %	Lines
virtualizarr/tests/test_backend.py	0.00%	3 Missing ⚠️
virtualizarr/backend.py	80.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #361      +/-   ##
==========================================
+ Coverage   79.74%   79.80%   +0.06%     
==========================================
  Files          51       51              
  Lines        3929     3951      +22     
==========================================
+ Hits         3133     3153      +20     
- Misses        796      798       +2     

Flag	Coverage Δ
unittests	79.80% <50.00%> (+0.06%)	⬆️

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[TomNicholas]

TIFF doesn't even work for Kerchunk-backed virtualization?

Not right now, see #291

(apologies for not thinking to put this as a draft first)

No worries at all - thank you for taking initiative to improve this!

[maxrjones]

I'm confident the test failures are unrelated to this PR but won't have time to investigate more until Thursday or Friday