Cosmic Ray: mutation testing for Python
“Four human beings – changed by space-born cosmic rays into something more than merely human.”
—The Fantastic Four
Cosmic Ray is a mutation testing tool for Python 3.
It makes small changes to your source code, running your test suite for each one. Here’s how the mutations look:
Read the full documentation at readthedocs.
Contributing
The easiest way to contribute is to use Cosmic Ray and submit reports for defects or any other issues you come across. Please see CONTRIBUTING.rst for more details.
Release files for cosmic-ray 8.7.0
For a detailed explanation of source distributions (sdists) and built distributions (wheels), please see the package formats documentation.
Source distribution (sdist)
| File | Size | Uploaded | |
|---|---|---|---|
| cosmic_ray-8.7.0.tar.gz | 1.7 MB | Details |
Built distribution (wheel)
| File | Interpreter | ABI | Platform | Reset |
|---|---|---|---|---|
| cosmic_ray-8.7.0-py3-none-any.whl | Python 3 | none | any | Details |
Total release size:1.7 MB
Release files / cosmic_ray-8.7.0.tar.gz
| Download URL | cosmic_ray-8.7.0.tar.gz |
|---|---|
| Size | 1.7 MB |
| Tags | Source |
|
SHA-256 checksum How to use checksums |
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BLAKE2b-256 checksum How to use checksums |
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| Upload date | |
|
Uploaded using Trusted Publishing? What is trusted publishing? |
Yes |
| Uploaded via |
twine/7.0.0 CPython/3.13.14
|
Provenance
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Transparency logRelease files / cosmic_ray-8.7.0-py3-none-any.whl
| Download URL | cosmic_ray-8.7.0-py3-none-any.whl |
|---|---|
| Size | 62.3 kB |
| Tags | Python 3 |
|
SHA-256 checksum How to use checksums |
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|
BLAKE2b-256 checksum How to use checksums |
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|
| Upload date | |
|
Uploaded using Trusted Publishing? What is trusted publishing? |
Yes |
| Uploaded via |
twine/7.0.0 CPython/3.13.14
|
Provenance
Provenance describes where a file came from. On PyPI, provenance is shared via attestations, which provide a verifiable record of the build or publishing details. View details, limitations and caveats.
PyPI Publish Attestation
PyPI verified that this artifact, at this checksum, originated from the publisher listed below.
Signed by GitHub Actions, verified by PyPI on Aug 9, 2026.
Transparency log