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Fairlead TestAvailable

Unit test generation

Autonomous unit tests for existing codebases.

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.

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Unit test coverage of one service

Get to 80%+ unit test coverage in weeks.

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

How it works

What it starts fromYour servicesource, build and existing testsGit historychange heat, fix and revert commitsScopethe paths and classes you chooseFor example, the module due for migration, or code no one on the team knows wellfairleadTESTYour teamMeasurecoverage per methodRankwhat to test firstScreentrivial or buggyPlantest scenariosWriteper languageDeliverPR/MR per repoMap-aware order1 untested code2 fixed, churning3 the restcompilespassessuite passesa failed checkis repaired orreplannedcannot betestedstill failingNot testable: hands over what it foundsuspectedbugSuspected bug: handed to fairleadFIXReviewPR/MR per repositoryUnit testsone commit per serviceTest manifestwhat is covered, what is notthen mergeInvestigatereport or MCPBlocked scenariosand what blocks each oneFailed test draftswith what went wrongin your IDE or agentBug fixits own PR/MRThe fixmade by fairleadFIXRegression testfails before, passes afterthen merge
Illustrative workflow. Not every scenario can be tested as the code stands, because of its architecture or your team’s conventions; those scenarios and the failed drafts go to your team rather than being dropped. Each run measures coverage again, so merged tests set the next starting point. Suspected bugs go to Fairlead Fix when it is enabled; otherwise that code is left out.
What it starts fromYour servicesource, build and existing testsGit historychange heat, fix and revert commitsScopethe paths and classes you chooseFor example, the module due for migration,or code no one on the team knows wellfairleadTESTMeasurecoverage per file and methodRankuntested, then often-fixed codeScreenskip trivial code, spot bugsPlanscenarios for each methodSuspected bugto fairleadFIXWriteJava, C# and Pythoncompilespassessuite passesa failed checkis repaired orreplannedstill failingNot testablehands overDeliverPR/MR per repositoryYour teamReviewPR/MR per repositoryUnit testsone commit per serviceTest manifestwhat is covered, what is notthen mergeBug fixits own PR/MRThe fixby fairleadFIXRegression testred, then greenthen mergeInvestigatereport or MCPBlocked scenariosand what blocks eachFailed test draftswhat went wrongin your IDE or agent
Illustrative workflow. Not every scenario can be tested as the code stands, because of its architecture or your team’s conventions; those scenarios and the failed drafts go to your team rather than being dropped. Each run measures coverage again, so merged tests set the next starting point. Suspected bugs go to Fairlead Fix when it is enabled; otherwise that code is left out.

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.

One unit test, four ways of writing it

Swipe the table

By handAI amendedLocal agentFairlead
Developer time for one test20 min10 min5 minNone
All in cost of one test$26.44$13.27$6.67$5.00

The 21,667 tests that take a million-line codebase from 15% to 80% cost $503K less with Fairlead than by hand in the first year. Unit test model at the calculator's default inputs.

What Fairlead Test saves you

A 12-month projection across four approaches. Adjust the five codebase parameters below and watch the model recompute live.

+429%

1-Year ROI · Fairlead Test

Return on autonomous unit test generation, measured against writing the same tests by hand.

ROI = (manual cost - Fairlead Test cost) ÷ Fairlead Test cost. Every approach is costed against the same delivered tests.

The codebase this team maintains. 5K to 2M

All in cost of one developer. 1K to 900K

Where the codebase starts. 0% to 79%

Where it should get to. 50% to 100%

What one escaped bug costs you, per test that would have caught it. 1 to 2K

Coverage reached

Every approach is costed to deliver the same tests, so they follow one coverage curve.

0%20%40%60%80%100%0123456789101112CoverageMonth80%

Cumulative cost ($K)

What it costs each approach to write and maintain the same tests.

$0K$150K$300K$450K$600K$750K0123456789101112Cost ($K)Month$117K$621K$312K$157K

Cumulative net value ($K)

Value of the bugs those tests prevent, after the cost of writing them.

$0K$1,500K$3,000K$4,500K$6,000K$7,500K0123456789101112Net value ($K)Month$5,258K$4,757K$5,065K$5,219K

Developer time not spent

Cumulative hours saved against writing the same tests by hand.

02,0004,0006,0008,00010,0000123456789101112HoursMonth7,82503,9135,869

$503,388 estimated cost avoided vs manual (1 yr)

Open the full calculator

The full calculator includes team capacity and the combined Test and Fix projection.

Outcomes

Coverage is maintained automatically as the code grows.

0 hrs

Developer time

80%+

Coverage, within weeks

5×

Lower cost per test than by hand

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