Sample work · Code & Bugs
Troubleshooting with regression test: incorrectly read amounts
An invoicing program read amounts incorrectly when thousands separators were present. First tests showing the error, then the smallest change, then all tests green. Report and change can be found here.
Sample work (demo), not a client job. Built as a trial task with invented example data; the check figures below come from the automatic test run and are not polished.
What was built
- First, regression tests that are red before the repair
- Then only the single faulty function changed
- Afterwards, the existing tests and the new ones green together
How it was checked
Automatic test run on 2026-10-31, taken from the log (test data invented, figures measured):
- 7/7 steps green
- Customer suite 9 tests, 9 regression tests (9 red before fix), after fix 18/18 green, changed: ['parse_betrag']
Limits
What this sample does not cover, so nobody expects more:
- Sample covers a Python bug with an existing pytest suite; bugs that occur only in production (load, third-party services, hardware) require customer logs/access
- Foreign languages/stacks without a local runtime (e.g., iOS, .NET desktop with license) not covered
- Fix is delivered only with tests, not deployed untested directly in the customer system
Something like this for your business?
Describe briefly what you need. You get a fixed price before I start; nothing happens without your yes.