mutatest: Python mutation testing
Are you confident in your tests? Try out mutatest and see if your tests will detect small
modifications (mutations) in the code. Surviving mutations represent subtle changes that are
undetectable by your tests. These mutants are potential modifications in source code that continuous
integration checks would miss.
Features
- Simple command line tool with multiple configuration options.
- Built on Python's Abstract Syntax Tree (AST) grammar to ensure mutants are valid.
- No source code modification, only the
__pycache__is changed.- Uses
coverageto create only meaningful mutants.- Built for efficiency with multiple running modes and random sampling of mutation targets.
- Capable of running parallel mutation trials with multiprocessing on Python 3.8.
- Flexible enough to run on a whole package or a single file.
- Includes an API for custom mutation controls.
- Tested on Linux, Windows, and MacOS with Azure pipelines.
- Full strict static type annotations throughout the source code and the API.
Install
Install from PyPI:
$ pip install mutatestInstall from conda-forge:
$ conda install -c conda-forge mutatestExample Output
This is an output example running mutation trials against the API Tutorial example folder example folder.
$ mutatest -s example/ -t "pytest" -r 314
Running clean trial
2 mutation targets found in example/a.py AST.
1 mutation targets found in example/b.py AST.
Setting random.seed to: 314
Total sample space size: 2
10 exceeds sample space, using full sample: 2.
Starting individual mutation trials!
Current target location: a.py, LocIndex(ast_class='BinOp', lineno=6, col_offset=11, op_type=<class '_ast.Add'>)
Detected mutation at example/a.py: (6, 11)
Detected mutation at example/a.py: (6, 11)
Surviving mutation at example/a.py: (6, 11)
Break on survival: stopping further mutations at location.
Current target location: b.py, LocIndex(ast_class='CompareIs', lineno=6, col_offset=11, op_type=<class '_ast.Is'>)
Detected mutation at example/b.py: (6, 11)
Running clean trial
Mutatest diagnostic summary
===========================
- Source location: /home/user/Github/mutatest/docs/api_tutorial/example
- Test commands: ['pytest']
- Mode: s
- Excluded files: []
- N locations input: 10
- Random seed: 314
Random sample details
---------------------
- Total locations mutated: 2
- Total locations identified: 2
- Location sample coverage: 100.00 %
Running time details
--------------------
- Clean trial 1 run time: 0:00:00.348999
- Clean trial 2 run time: 0:00:00.350213
- Mutation trials total run time: 0:00:01.389095
Trial Summary Report:
Overall mutation trial summary
==============================
- DETECTED: 3
- SURVIVED: 1
- TOTAL RUNS: 4
- RUN DATETIME: 2019-10-17 16:57:08.645355
Detected mutations:
DETECTED
--------
- example/a.py: (l: 6, c: 11) - mutation from <class '_ast.Add'> to <class '_ast.Sub'>
- example/a.py: (l: 6, c: 11) - mutation from <class '_ast.Add'> to <class '_ast.Mod'>
- example/b.py: (l: 6, c: 11) - mutation from <class '_ast.Is'> to <class '_ast.IsNot'>
Surviving mutations:
SURVIVED
--------
- example/a.py: (l: 6, c: 11) - mutation from <class '_ast.Add'> to <class '_ast.Mult'>Documentation
For full documentation, including installation, CLI references, API references, and tutorials, please see https://mutatest.readthedocs.io/en/latest/. The project is hosted on PyPI at https://pypi.org/project/mutatest/.
Bugs/Requests
Please use the GitHub issue tracker to submit bugs or request features. See the Contributing Guidelines if you are interested in submitting code in the form of pull requests.
ChangeLog
Consult the Changelog page for fixes and enhancements of each version.
License
Copyright Evan Kepner 2018-2020.
Distributed under the terms of the MIT
license, mutatest is free and open source software.