Certification confirmation tests broken since Click.confirm() and async usage

• Since click.confirm() usage in e7b6e26b.
  • Should be fixable with https://click.palletsprojects.com/en/7.x/testing/#input-streams
• Since asynchronism usage in 583c3d48:
  • #225 (closed): Install pytest-asyncio
  • Unfortunately, Click does not handle async. And the return Result object does not contains values but only defaults one. It does return like a coroutine instead of the Result object.