testbot + group non-atomic tests

[mixmix]

I noticed we weren't using the testbot everywhere. Changed that to main maintenance easier. I also considered making all test atomic so the repo was consistent, but the remaining tests were too fidey to do this with - instead I just modified the structure to make it very clear that tests depend on one another

• left a comment
• used t.test to provide a clear scope
  • this is needed so that you can have t.only work because starting sbots in the global scope means t.only was never exiting :angry:

[staltz]

I'm confused with what happened to all these PRs. I approved my PR-of-your-PR, but apparently you had changed its base to become a PR-to-master, and now we have these commits in master branch:

• make tests atomic, add persistence tests
• revert promise tests to cb tests

But then this PR also has those two commits, plus a git conflict. Also PR #75 has a git conflict. And why was #73 closed?

What's going on??