Crate dev_mutate 

dev-mutate

Mutation testing for Rust. Wraps cargo-mutants and emits results as dev_report::Report.

Mutation testing makes small deliberate changes to your code — flipping < to >, changing + to -, removing a return. It then runs your tests against each mutation. A test suite that catches the mutations kills them; surviving mutations are evidence the suite isn’t actually testing that behavior.

Kill rate

kill_pct = killed / (killed + survived) * 100

Timeouts MUST NOT count toward either numerator or denominator — they don’t reflect test quality (REPS § 3).

Quick example

use dev_mutate::{MutateRun, MutateThreshold};

let run = MutateRun::new("my-crate", "0.1.0");
let result = run.execute().unwrap();

let threshold = MutateThreshold::min_kill_pct(70.0);
let check = result.into_check_result(threshold);

Requirements

cargo install cargo-mutants

The crate detects absence and surfaces MutateError::ToolNotInstalled without panicking.

Structs

FileBreakdown

Per-file mutation outcome counts and derived kill rate.

MutateProducer

Producer adapter that drives a MutateRun and converts the result into a Report against the configured MutateThreshold.

MutateResult

Result of a mutation testing run.

MutateRun

Configuration for a mutation testing run.

SurvivingMutant

A surviving mutant — one the test suite did NOT catch.

Enums

MutateError

Errors that can arise during a mutation testing run.

MutateThreshold

Threshold defining the minimum acceptable kill rate.