Issues with running fancy-tests in mocha with --parallel

[mdonnalley]

There are a couple of issues that happen when you attempt to run mocha tests in parallel.

The first is that a non-determinate number of tests are skipped. This problem seems to be resolved by explicitly import it from mocha instead of relying on the global here, https://github.com/oclif/fancy-test/blob/main/src/base.ts#L6

The second is that once you resolve the first, tests fail randomly. My best guess is that fancy-test is maintaining some global state that gets mangled when you run tests in parallel.

[git2gus]

This issue has been linked to a new work item: W-14208326