# Fairlead Test: Autonomous unit tests for existing codebases.

Canonical: https://fairleadhq.com/platform/products/test/

Updated: 2026-09-21
Publication state: published
Product version: available

Agent summary: Fairlead Test: A reliable algorithmic workflow that raises coverage with high-quality unit tests, delivered as pull requests, with zero developer effort. Model-agnostic across leading models, with per-language logic built for each codebase.

## Prerequisites

- None declared.

## Inputs

- None declared.

## Outputs

- None declared.

## Limitations

- None declared.

## Permissions

- None declared.

## Privacy

- None declared.


Unit tests for the codebase you already have, generated per language, compiled and run before they reach you, and delivered as pull requests.

Status: Available

- 80%+: Coverage lift in weeks
- 0 min: Developer time per test
- ~60%: 1-year ROI (cost savings vs manual)
- ~$5.3M: Expected monetary value in the first year
- ~$71K: Saved vs manual (1 yr)

## How it works

1. Measure: Build the service and measure coverage per file and per method at the start of every run, limited to the paths and classes you choose.
2. Rank: Decide what to test first. By coverage gaps alone, or map-aware, which puts untested code first and then code that git history shows is often fixed or keeps changing.
3. Screen: Skip trivial methods and look for suspected bugs. With Fairlead Fix enabled, a suspected bug gets its own PR/MR with the fix and a regression test; otherwise that code is left out.
4. Plan: Write test scenarios for each method, and confirm the existing test suite passes before any test is added.
5. Write: Generate tests per language, today Java, C# and Python. Each test must compile and pass, and the full suite must still pass. Failed checks are repaired or replanned within limits.
6. Hand over: Not every scenario can be tested as the code stands, because of its architecture or your team's conventions. Nothing is dropped. Blocked scenarios, what blocks each one, and failed test drafts go to your team as a report or over MCP, for a developer or an agent to pick up.
7. Deliver: Deliver a pull or merge request per repository, one commit per service, with a manifest of what was covered and what was left out. Your team decides whether to merge.

## What it does

- Coverage analyser and strategy planner: Slices the codebase by coverage and criticality, then plans where new tests deliver the most value.
- Language-specific generation: Logic built per language, Java and Python today, with C#, JavaScript, TypeScript, Go and Rust on the way. Tests compile, run, and reflect real usage from the first commit.
- Model-agnostic, language-specific: Model-agnostic across major providers, with logic built for each language, not a generic assistant that treats every codebase the same. Your code stays private throughout.
- Delivered as pull requests: Tests land as pull requests in your repository, which makes refactoring safe and takes risk out of modernisation work.

## Outcomes

- 0 hrs: Developer time
- 80%+: Coverage, within weeks
- 5×: Lower cost per test than by hand
- Coverage is maintained automatically as the code grows.