Test with VNU REST API

[bollwyvl]

References

• sub-pr of use the conda forge implementation on the vnu-validator #17

Elevator Pitch

This uses the vnu REST API to stand up a single HTTP server, and then requests to do POST requests.

At present, with only two tests that use this fixture, it's hard to assess whether it's worth the complexity, but at scale, it almost certainly would be.

Also, of note, the members of violations that come back don't have the url attribute. Presumably, this could be added back in.

Changes

• normalize CI test setup
  • avoid some warnings with JUPYTER_PLATFORM_DIRS
  • use all conda-forge deps
  • enable rest of dev experience with .github/test-environment.yml
  • use a package.json and yarn.lock to get a reproducible version of axe-core
• run linter
• add fixtures for wrapping vnu server singleton
• adds some env vars
  • NBA11Y_VNU_SERVER_URL (default: ``)
    • if not set, consult the following
      • NBA11Y_JAVA_PATH (default: ``, fallback: shutil.which('java'))
      • NBA11Y_VNU_JAR_PATH (default: ``, fallback: shutil.which('vnu'))
  • NBA11Y_CHROMIUM_CHANNEL (default: chrome-beta)
    • I don't let MS install rando stuff on my box as root, so have only tested with chromium