A function returns the wrong value, an endpoint crashes on certain input, or code stopped working after a library update. I first write a test that reproduces the bug, then fix the code until that test passes and your existing tests still pass. You see the proof: the new test fails on the old code and passes on the new one. In the larger packages I add tests for the module and can replace an outdated library while keeping the behavior identical, checked by tests run before and after. You get a patch or pull request, the tests and a short explanation of the cause.

This service: One bug fixed - One reproducible bug fixed, with a test that fails before and passes after. USD 129, delivered in 2 days, 1 revision.

Larger scope on request: Bug fix plus tests (Fix plus unit and API tests for the affected module) for USD 299 in 5 days, or Fix and modernize (Fix, tests, and replace one outdated library without changing behavior) for USD 690 in 10 days. Message me and I send a custom offer.

What I need from you: Access to the repository or the relevant files, steps to reproduce the bug, expected versus actual result, and how you run the project or its tests today.

How it works: 1) Reproduce: A failing test that shows the bug. 2) Fix: Code fixed until the new and all existing tests pass. 3) Handover: Patch or pull request, tests, cause explained in plain words.