7ee4bcd4

By: Tom Sydney Kerckhove <syd@cs-syd.eu>

Log per-test coverage progress and skip empty coverage runs

Adds typed CoverageProgressEvent rendered to [[Chunk]] (matching the
existing MutationProgressEvent pattern) covering:

- per-test running/done events emitted to stderr from runCoverageMode
- skip events when the manifest has no records or the spec has no tests

Also throws an explicit nix-side error when mutationCheck is called with
no test suites, and bumps opt-env-conf to pull in the many/some
exponential-time fix.

Timeline