Move tests to github

[joehoyle]

Fixes #697

[kadamwhite]

Sounds good then!

[hm-backport]

The backport to v3-branch failed:

Commits ["78f9f419579f48df4a635d17f8e3a0f2d3042697","560b12c86e6a179a47aa8dcc41892b33fe304d80","3040810a49e94234d02f1a86f7d4a0f81f4ed39a","2e0a76d07f1a289c8ee8997e1c7e03e148c6054b","243835a12dadc7f5ae1f40dbf35fc660c4bbfce6","33e0f79209374ec4dd252e78961ba7130e2021e2","a149289308944e7bc7155b529fc95e288571cb51","9b9ed3841f6981fc32b2c96bfb96dfda73af0bb9","2bae209d43a84bc3c162a2e9d1d07c797ed10320"] could not be cherry-picked on top of v3-branch

To backport manually, run these commands in your terminal:

# Fetch latest updates from GitHub.
git fetch
# Create new working tree.
git worktree add .worktrees/backport v3-branch
# Navigate to the new directory.
cd .worktrees/backport
# Cherry-pick all the commits of this pull request and resolve the likely conflicts.
git cherry-pick 78f9f419579f48df4a635d17f8e3a0f2d3042697 560b12c86e6a179a47aa8dcc41892b33fe304d80 3040810a49e94234d02f1a86f7d4a0f81f4ed39a 2e0a76d07f1a289c8ee8997e1c7e03e148c6054b 243835a12dadc7f5ae1f40dbf35fc660c4bbfce6 33e0f79209374ec4dd252e78961ba7130e2021e2 a149289308944e7bc7155b529fc95e288571cb51 9b9ed3841f6981fc32b2c96bfb96dfda73af0bb9 2bae209d43a84bc3c162a2e9d1d07c797ed10320
# Create a new branch with these backported commits.
git checkout -b backport-698-to-v3-branch
# Push it to GitHub.
git push --set-upstream origin backport-698-to-v3-branch
# Go back to the original working tree.
cd ../..
# Delete the working tree.
git worktree remove .worktrees/backport

Then, create a pull request where the base branch is v3-branch and the compare/head branch is backport-698-to-v3-branch.