Exit codes

cargo-mutants returns an exit code that can be used by scripts or CI.

• 0: Success! Every viable mutant that was tested was caught by a test.

• 1: Usage error: bad command-line arguments etc.

• 2: Found some mutants that were not covered by tests.

• 3: Some tests timed out: possibly the mutatations caused an infinite loop, or the timeout is too low.

• 4: The tests are already failing or hanging before any mutations are applied, so no mutations were tested.

For more detailed machine-readable information, use the mutants.out directory.