# hcoles/pitest

State of the art mutation testing system for the JVM

Repository: https://github.com/hcoles/pitest
Canonical: https://ross.abutalabs.com/products/pitest
Language: Java
License: Apache-2.0
License Family: permissive
Topics: mutation-analysis, mutation-testing, coverage, junit, testng, testing, java
Last push: 2026-08-25T15:44:05+00:00

## Health v2 (maintenance only)
Score: 98/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 99, release rhythm 96, longevity 100
- inputs: {"age_days": 4621, "days_push": 8, "days_rel": 29, "gap_med": 14.5, "n_releases_24m": 41}
- flags: none
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 1851, forks 372 (observed 2026-08-28T04:05:44.372908+00:00)

## What it is
Pitest (PIT) is a state-of-the-art mutation testing system for Java and the JVM. It mutates bytecode to verify the effectiveness of unit tests, integrating with JUnit, TestNG, and build tools like Maven and Gradle.

## Use cases
- measure how good my unit tests really are
- run mutation testing on a Java project
- find gaps in test coverage beyond line coverage
- check that tests actually catch bugs
- score test suite quality for a JVM codebase

## When to choose
- you write Java/Kotlin/JVM code and want to assess test strength via mutation analysis
- you use JUnit or TestNG and want build-tool integration
- you need an actively maintained, mature mutation testing tool

## When to avoid
- your codebase is not on the JVM
- you need quick feedback in tight CI time budgets, since mutation testing is compute-intensive
- you only need simple line/branch coverage rather than mutation scores

## Facets
- artifact type: library
- maturity: active
- function: testing, benchmarking, developer-tools
- domain: testing, developer-tools
- platform: jvm, cli
- tags: mutation-testing, junit, testng, code-coverage, bytecode, maven-plugin, gradle-plugin, jvm

## Member repositories
- hcoles/pitest (main) score 98

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:05:44.372908+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-30T03:16:55.375865+00:00, confidence not recorded.
  - readme: https://github.com/hcoles/pitest (fetched 2026-08-28T04:05:44.372908+00:00, sha 1ba40790a62e)
- Data as of 2026-08-30T08:39:29.467469+00:00.