Zarr 2.9.1: fix conda release

[joshmoore]

see:

• zarr v2.9.0 conda-forge/zarr-feedstock#48
• fsspec tests are not auto-skipped in test_dim_separator #817

The conda-forge release failed since fsspec is not installed by default. In order to get Zarr deployed ASAP (re: DiamondLightSource/python-tristan#62) this simply properly handles the test issue that @QuLogic brought up in #817.

It might be that moving forward, fsspec should be installed & tested for conda-forge releases. If not, then a minimal test workflow should be added here to show that the conda-forge requirements (below) suffice to run or skip all tests:

channels:
  - conda-forge
  - defaults
dependencies:
  - python < 3.9.0
  - wheel
  - numcodecs
  - numpy
  - pip
  - pip:
    - asciitree
    - fasteners
    - pytest
    - setuptools_scm

[codecov]

Codecov Report

Merging #819 (c6d1a97) into master (adc430a) will increase coverage by 0.00%.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##           master     #819   +/-   ##
=======================================
  Coverage   99.85%   99.85%           
=======================================
  Files          31       31           
  Lines       10613    10614    +1     
=======================================
+ Hits        10598    10599    +1     
  Misses         15       15           

Impacted Files	Coverage Δ
zarr/tests/test_dim_separator.py	97.61% <100.00%> (+0.05%)	⬆️

[joshmoore]

Still ignoring codecov (opinions welcome) and moving forward with this to unblock conda.

[benjaminhwilliams]

I'm not sure whether you welcome reviews from outsiders to the project, but I think there's slightly more to the Conda release failure than just catching absent fsspec. See my suggestion.

[benjaminhwilliams]

I think there's an additional problem with test_open[static_flat] and test_open[static_nested], which is also blocking the Conda release. The Pytest working directory does not contain the expected paths fixture/flat and fixture/nested, which becomes clearer if you're stricter about the persistence mode you use in test_open:

Suggested change

	verify(zarr.open(dataset))
	verify(zarr.open(dataset, "r"))

[benjaminhwilliams]

This has the added benefit of guarding against accidentally leaving any little droppings in the Pytest working directory.

[joshmoore]

Hi @benjaminhwilliams, I at least welcome it! ;) Would you be up for opening this as a PR?

[benjaminhwilliams]

Sure. This small suggestion only highlights the issue, it doesn't fix the problem that the Pytest working directory is not the project root, as the test appears to assume. But we can fix that by discussion in the PR. I'll open it and request your review.