E-e-topy·May 25, 2025Submission
Mutmut – Python Mutation Tester
20 points · Open discussionboxed
mutmut
Python2019–2025
boxed / mutmut
mutmut
Mutation testing system
3Distinct people
4Mentions
0Explicit recommenders
1.5KGitHub stars
What to know before exploring
What it is
Mutation testing system
GitHub
Where it is used
No documented product use has been verified yet.
What people are saying
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Also in these discussions
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This week on Hacker News
Nov 7–Nov 14 UTC · Direct repository links and separately labeled related project stories. Indexed through 11/14/2026, 12:54:37 PM UTC.
No direct repository links were found in the indexed HN discussions over the past seven days. Older discussions are available below.
Mentions over time
HN mentions by year4 dated mentions
Observed mentions: 2019-01-17 00:22:34 UTC to 2025-05-25 13:38:46 UTC.
Counts come from the repository’s dated source evidence. Index cutoff: 2026-11-02 08:16:59 UTC.
View mention counts and date ranges
| Period | Start (UTC) | End (exclusive, UTC) | Mentions | Submissions | Comments |
|---|---|---|---|---|---|
| 2019 | 2019-01-01 00:00:00 UTC | 2020-01-01 00:00:00 UTC | 2 | 0 | 2 |
| 2020 | 2020-01-01 00:00:00 UTC | 2021-01-01 00:00:00 UTC | 0 | 0 | 0 |
| 2021 | 2021-01-01 00:00:00 UTC | 2022-01-01 00:00:00 UTC | 0 | 0 | 0 |
| 2022 | 2022-01-01 00:00:00 UTC | 2023-01-01 00:00:00 UTC | 0 | 0 | 0 |
| 2023 | 2023-01-01 00:00:00 UTC | 2024-01-01 00:00:00 UTC | 1 | 0 | 1 |
| 2024 | 2024-01-01 00:00:00 UTC | 2025-01-01 00:00:00 UTC | 0 | 0 | 0 |
| 2025 | 2025-01-01 00:00:00 UTC | 2026-01-01 00:00:00 UTC | 1 | 1 | 0 |
What Hacker News says
4 sourcesI wrote one (https://github.com/boxed/scientist) as I found the existing ones very complicated and that just gives me a bad feeling. Since I'm the author of mutmut (https://github.com/boxed/mutmut), I also made sure my implementation was 100% mutation tested before I used it in production.
I used my implementation to replace number parsing in my work project: https://kodare.net/2021/04/04/safe_number_parsing.html
In Scientist: A Ruby library for carefully refactoring critical pathsSome tools for mutation testing in Python:
- https://github.com/boxed/mutmut
- https://github.com/sixty-north/cosmic-ray
In 99% code coverage (2017)Would that be done based on which (different) tests killed a particular mutant?
Often an integration test would catch the multiple mutations also being caught by (different) unit tests.
I assume that you mean that if a certain (broader) test kills the same mutants as X unit tests, those X tests are not really necessary?
I've looked into https://github.com/boxed/mutmut and https://github.com/sixty-north/cosmic-ray for Python project, and there it is only important that a mutant gets killed, but not how often and by which tests (therefore you can use `pytest -x` to continue with the next mutation after the first test failed due to it).
In 99% code coverage (2017)