Run Zarr CI tests out-of-tree

[jakirkham]

Currently we run Zarr tests in-tree, which means things like fixture are present. However these might not show up correctly when installing the package (for example: #1312 (comment) ). If Zarr were installed on CI (similar to how a user would) and then we changed to a different directory (outside of the Zarr source tree), we should be able to catch this installation issues within PRs.

[sanketverma1704]

Hi @jakirkham. Thanks for opening the issue.

After conda-forge/zarr-feedstock#73 failed yesterday, I tried to understand what was going wrong and had a small discussion with @joshmoore.

One of the ways that Josh suggested was that if we move fixture under zarr it would solve this, but we would be shipping the fixture every time during Zarr installation. This would increase the package's overall size and maybe the installation time.

Is there any way you think we can approach this problem?

Also, CC'ing @zarr-developers/python-core-devs if you have any thoughts on this.

[jakirkham]

In the past one typically would use MANIFEST.in to include the data files in the sdist, but not necessarily packages (to keep from getting bloated).

Would suggest running through some of the options here.

setuptools_scm may also have a better way to handle this.