Thresholds

By default run passes whatever the score. run -threshold 0.8 fails the run when score is below 0.8, and -threshold-covered 0.9 when covered_score is below 0.9 (PIT mutationThreshold / testStrengthThreshold, Stryker thresholds.break); either fails only after report.json is written, and a run with nothing to score passes. The threshold and threshold_covered attributes of mutation_test pass them through, turning the target into a gate, and the other outputs are still written. Under sharding each shard checks its own mutants; the whole-package score needs the shards’ reports merged.