Initial unit test framework

[JonatanAntoni]

Fixes

• #

Changes

• Provide unit test framework requirements
• stub for vscode

Screenshots

Checklist

[jreineckearm]

Thanks a lot for this and bringing test coverage up to a baseline while the repo size is still manageable to catch up with!
Only discussion point is whether we want to show the Code Climate badges on the VS Code Marketplace/in VS Code which will happen if we don't strip them from the README before/during packaging.

[jreineckearm]

Good improvements! Will merge as is. But create another PR to remove the badges before packaging. Not keen on showing code climate reports on the marketplace or in the VS Code extension manager at this point. Yet, I like to see the stats on the repo itself.