Metadata-Version: 2.1
Name: mutatest
Version: 0.6.0.dev0
Summary: Python mutation testing.
Home-page: https://github.com/EvanKepner/mutatest
Author: Evan Kepner
Author-email: EvanKepner@users.noreply.github.com
Maintainer: Evan Kepner
License: MIT
Project-URL: Documentation, https://github.com/EvanKepner/mutatest
Project-URL: Bug Tracker, https://github.com/EvanKepner/mutatest/issues
Project-URL: Source Code, https://github.com/EvanKepner/mutatest
Description: :code:`mutatest`: Python mutation testing
        ==========================================
        
        
        .. image:: https://img.shields.io/badge/Python_version-3.7-green.svg
            :target: https://www.python.org/
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            :target: https://travis-ci.org/EvanKepner/mutatest
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          :target: https://codecov.io/gh/EvanKepner/mutatest
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        .. image:: https://pepy.tech/badge/mutatest
            :target: https://pepy.tech/project/mutatest
        
        
        
        Are you confident in your tests? Try out :code:`mutatest` and see if your tests will detect small
        modifications (mutations) in the code. Surviving mutations represent subtle changes that might
        slip past your continuous integration checks and are undetectable by your tests.
        
        
        Features:
            - Simple command line tool.
            - Integrated with :code:`coverage` to only create meaningful mutants.
            - Built on Python's Abstract Syntax Tree (AST) grammar to ensure mutants are valid.
            - Built for efficiency with multiple running modes and random sampling of mutation targets.
            - Does not modify your source code, only the :code:`__pycache__`.
            - Flexible enough to run on a whole package or a single file.
        
        
        Installation
        ============
        
        :code:`mutatest` requires Python 3.7. You can install with :code:`pip`:
        
        .. code-block:: bash
        
            $ pip install mutatest
        
        
        Alternatively, clone this repo and install locally:
        
        
        .. code-block:: bash
        
            $ cd mutatest
            $ pip install .
        
        
        :code:`mutatest` is designed to work when your test files are separated from your source directory
        and are prefixed with :code:`test_`. See `Pytest Test Layout`_ for more details.
        
        
        Using ``mutatest``
        ==================
        
        :code:`mutatest` is designed to be a diagnostic command line tool for your test coverage assessment.
        
        The mutation trial process follows these steps when :code:`mutatest` is run:
        
        1. Scan for your existing Python package, or use the input source location.
        2. Create an abstract syntax tree (AST) from the source files.
        3. Identify locations in the code that may be mutated (line and column). If you are running with
           :code:`coverage` the sample is restricted only to lines that are marked as covered in the
           :code:`.coverage` file.
        4. Take a random sample of the identified locations.
        5. Apply a mutation at the location by modifying a copy of the AST and writing a new cache file
           to the appropriate :code:`__pycache__` location with the source file statistics.
        6. Run the test suite. This will use the mutated :code:`__pycache__` file since the source statistics
           are the same for modification time.
        7. See if the test suite detected the mutation by a failed test.
        8. Remove the modified :code:`__pycache__` file.
        9. Repeat steps 5-9 for the remaining selected locations to mutate.
        10. Write an output report of the various mutation results.
        
        A "clean trial" of your tests is run before any mutations are applied. This same "clean trial" is
        run at the end of the mutation testing. This ensures that your original test suite passes before
        attempting to detect surviving mutations and that the :code:`__pycache__` has been appropriately
        reset when the mutation trials are finished.
        
        
        Specifying source files and test commands
        -----------------------------------------
        
        If you have a Python package in a directory with an associated :code:`tests/` folder
        (or internal :code:`test_` prefixed files, see the examples below) that are auto-detected
        with :code:`pytest`, then you can run :code:`mutatest` without any arguments.
        
        
        .. code-block:: bash
        
            $ mutatest
        
        It will detect the package, and run :code:`pytest` by default. If you want to run with special
        arguments, such as to exclude a custom marker, you can pass in the :code:`--testcmds` argument
        with the desired string.
        
        Here is the command to run :code:`pytest` and exclude tests marked with :code:`pytest.mark.slow`.
        
        .. code-block:: bash
        
            $ mutatest --testcmds "pytest -m 'not slow'"
        
            # using shorthand arguments
            $ mutatest -t "pytest -m 'not slow'"
        
        You can use this syntax if you want to specify a single module in your package to run and test.
        
        .. code-block:: bash
        
            $ mutatest --src mypackage/run.py --testcmds "pytest tests/test_run.py"
        
            # using shorthand arguments
            $ mutatest -s mypackage/run.py -t "pytest tests/test_run.py"
        
        
        There is an option to exclude files from the source set. By default, :code:`__init__.py` is
        excluded. Exclude files using the :code:`--exclude` argument with a space delimited list of files
        in a string. Only list the file name, not paths.
        
        .. code-block:: bash
        
            $ mutatest --exclude "__init__.py _devtools.py"
        
            # using shorthand arguments
            $ mutatest -e "__init__.py _devtools.py"
        
        
        Coverage optimization
        ---------------------
        
        Any command combination that generates a :code:`.coverage` file will use that as a restriction
        mechanism for the sample space to only select mutation locations that are covered. For example,
        running:
        
        .. code-block:: bash
        
            $ mutatest --testcmds "pytest --cov=mypackage tests/test_run.py"
        
            # using shorthand arguments
            $ mutatest -t "pytest --cov=mypackage tests/test_run.py"
        
        
        would generate the :code:`.coverage` file based on :code:`tests/test_run.py`. Therefore, even though
        the entire package is seen only the lines covered by :code:`tests/test_run.py` will be mutated
        during the trials. You can override this behavior with the :code:`--nocov` flag on the command line.
        
        If you have a :code:`pytest.ini` file that includes the :code:`--cov` command the default behavior
        of :code:`mutatest` will generate the coverage file. You will see this in the CLI output at the
        beginning of the trials:
        
        .. code-block:: bash
        
            $ mutatest -n 4 -t "pytest --cov=mypackage"
        
            ... prior output...
        
            ... Get mutatest targets from AST.
            ... Full sample space size: 115
            ... Coverage optimized sample space size: 75
            ... Selecting 4 locations from 75 potentials.
        
            ... continued output...
        
        
        Auto-detected package structures
        --------------------------------
        
        The following package structures would be auto-detected if you ran :code:`mutatest` from the
        same directory holding :code:`examplepkg/`. You can always point to a specific directory using
        the :code:`--source` argument. These are outlined in the `Pytest Test Layout`_ documentation.
        
        
        Example with internal tests
        ~~~~~~~~~~~~~~~~~~~~~~~~~~~
        
        .. code-block:: bash
        
            .
            └── examplepkg
                ├── __init__.py
                ├── run.py
                └── test_run.py
        
        
        Example with external tests
        ~~~~~~~~~~~~~~~~~~~~~~~~~~~
        
        .. code-block:: bash
        
            .
            ├── examplepkg
            │   ├── __init__.py
            │   └── run.py
            └── tests
                └── test_run.py
        
        
        
        Selecting a running mode
        ------------------------
        
        :code:`mutatest` has different running modes to make trials faster. The running modes determine
        what will happen after a mutation trial. For example, you can choose to stop further mutations at a
        location as soon as a survivor is detected. The different running mode choices are:
        
        Run modes:
            - f: full mode, run all possible combinations (slowest but most thorough).
            - s: break on first SURVIVOR per mutated location e.g. if there is a single surviving mutation
              at a location move to the next location without further testing.
              This is the default mode.
            - d: break on the first DETECTION per mutated location e.g. if there is a detected mutation on
              at a location move to the next one.
            - sd: break on the first SURVIVOR or DETECTION (fastest, and least thorough).
        
        The API for :code:`mutatest.controller.run_mutation_trials` offers finer control over the run
        method beyond the CLI.
        
        A good practice when first starting is to set the mode to :code:`sd` which will stop if a mutation
        survives or is detected, effectively running a single mutation per candidate location. This is the
        fastest running mode and can give you a sense of investigation areas quickly.
        
        .. code-block::
        
            $ mutatest --mode sd
        
            # using shorthand arguments
            $ mutatest -m sd
        
        Controlling randomization behavior and trial number
        ---------------------------------------------------
        
        :code:`mutatest` uses random sampling of all source candidate locations and of potential mutations
        to substitute at a location. You can set a random seed for repeatable trials using the
        :code:`--rseed` argument. The :code:`--nlocations` argument controls the size of the sample
        of locations to mutate. If it exceeds the number of candidate locations then the full set of
        candidate locations is used.
        
        .. code-block::
        
            $ mutatest --nlocations 5 --rseed 314
        
            # using shorthand arguments
            $ mutatest -n 5 -r 314
        
        
        Setting the output location
        ---------------------------
        
        By default, :code:`mutatest` will write a :code:`mutation_report.rst` to the current working
        directory. You can set this file name and path location using the :code:`--output` argument.
        
        .. code-block::
        
            $ mutatest --output path/to/my_custom_file.rst
        
            # using shorthand arguments
            $ mutatest -o path/to/my_custom_file.rst
        
        
        The output report will include the arguments used to generate it along with the total runtimes.
        The SURVIVORS section of the output report is the one you should pay attention to. These are the
        mutations that were undetected by your test suite. The report includes file names, line numbers,
        column numbers, original operation, and mutation for ease of diagnostic investigation.
        
        
        Putting it all together
        -----------------------
        
        If you want to run 5 trials, in fast :code:`sd` mode, with a random seed of 345 and an output
        file name of :code:`mutation_345.rst`, you would do the following if your directory structure
        has a Python package folder and tests that are auto-discoverable and run by :code:`pytest`.
        
        .. code-block:: bash
        
            $ mutatest -n 5 -m sd -r 345 -o mutation_345.rst
        
        
        With :code:`coverage` optimization if your :code:`pytest.ini` file does not already specify it:
        
        .. code-block:: bash
        
            $ mutatest -n 5 -m sd -r 345 -o mutation_345.rst -t "pytest --cov=mypackage"
        
        
        Getting help
        ------------
        
        Run :code:`mutatest --help` to see command line arguments and supported operations:
        
        .. code-block:: bash
        
            $ mutatest --help
        
            usage: Mutatest [-h] [-e STR_LIST] [-m {f,s,d,sd}] [-n INT] [-o PATH] [-r INT]
                            [-s PATH] [-t STR_CMDS] [--debug]
        
            Python mutation testing. Mutatest will manipulate local __pycache__ files.
        
            optional arguments:
              -h, --help            show this help message and exit
              -e STR_LIST, --exclude STR_LIST
                                    Space delimited string list of .py file names to exclude. (default: '__init__.py')
              -m {f,s,d,sd}, --mode {f,s,d,sd}
                                    Running modes, see the choice option descriptions below. (default: s)
              -n INT, --nlocations INT
                                    Number of locations in code to randomly select for mutation from possible targets. (default: 10)
              -o PATH, --output PATH
                                    Output file location for results. (default: mutation_report.rst)
              -r INT, --rseed INT   Random seed to use for sample selection.
              -s PATH, --src PATH   Source code (file or directory) for mutation testing. (default: auto-detection attempt).
              -t STR_CMDS, --testcmds STR_CMDS
                                    Test command string to execute. (default: 'pytest')
              --debug               Turn on DEBUG level logging output.
              --nocov               Ignore coverage files for optimization.
        
        Supported Mutations
        ===================
        
        :code:`mutatest` is early in development and supports the following mutation operations based
        on the `Python AST grammar`_:
        
        Supported operations:
            - :code:`AugAssign` mutations e.g. :code:`+= -= *= /=`.
            - :code:`BinOp` mutations e.g. :code:`+ - / *`.
            - :code:`BinOp Bitwise Comparison` mutations e.g. :code:`x&y x|y x^y`.
            - :code:`BinOp Bitwise Shift` mutations e.g. :code:`<< >>`.
            - :code:`BoolOp` mutations e.g. :code:`and or`.
            - :code:`Compare` mutations e.g. :code:`== >= < <= !=`.
            - :code:`Compare In` mutations e.g. :code:`in, not in`.
            - :code:`Compare Is` mutations e.g. :code:`is, is not`.
            - :code:`Index` mutations e.g. :code:`i[0]` becomes :code:`i[1]` and :code:`i[-1]`.
            - :code:`NameConstant` mutations e.g. :code:`True`, :code:`False`, and :code:`None`.
        
        
        Adding more operations is a great area for contributions!
        
        Known limitations
        -----------------
        
        Since :code:`mutatest` operates on the local :code:`__pycache__` it is a serial execution process.
        This means it can be slow, and will take as long as running your test suite in series for the
        number of operations. It's designed as a diagnostic tool, not something you would run in your
        CICD pipeline. You could achieve parallel execution by orchestrating containers to hold
        individual copies of your module and executing subsets of your tests.
        
        If you kill the :code:`mutatest` process before the trials complete you may end up
        with partially mutated :code:`__pycache__` files. If this happens the best fix is to remove the
        :code:`__pycache__` directories and let them rebuild automatically the next time your package is
        imported (for instance, by re-running your test suite).
        
        The mutation status is based on the return code of the test suite e.g. 0 for success, 1 for failure.
        :code:`mutatest` can theoretically be run with any test suite that you pass with the
        :code:`--testcmds` argument; however, only :code:`pytest` has been tested to date. The
        :code:`mutatest.maker.MutantTrialResult` namedtuple contains the definitions for translating
        return codes into mutation trial statuses.
        
        
        .. target-notes::
        .. _Python AST grammar: https://docs.python.org/3/library/ast.html#abstract-grammar
        .. _Pytest Test Layout: https://docs.pytest.org/en/latest/goodpractices.html#choosing-a-test-layout-import-rules
        
        
        Changelog
        =========
        
        :code:`mutatest` is alpha software, and backwards compatibility between releases is
        not guaranteed while under development.
        
        0.6.0
        -----
        
            - Including :code:`pytest` in the installation requirements. Technically, any test runner can
              be used but with all base package assumptions being built around :code:`pytest` this feels
              like the right assumption to call out as an install dependency. It is the default behavior.
            - Updated :code:`controller` for test file exclusion to explicitly match prefix or suffix cases
              for :code:`"test_"` and :code:`"_test"` per :code:`pytest` conventions.
            - Changed error and unknown status results to console color as yellow instead of red.
            - Added mutiple invariant property tests, primarily to :code:`controller` and :code:`cache`.
            - Added :code:`hypothesis` to the test components of :code:`extras_require`.
            - Moved to :code:`@property` decorators for internal class properties that should only
              be set at initialization, may add custom :code:`setters` at a later time.
            - Fixed a zero-division bug in the :code:`cli` when reporting coverage percentage.
        
        0.5.0
        -----
        
            - Addition of :code:`optimizers`, including the new class :code:`CoverageOptimizer`.
            - This optimizer restricts the full sample space only to source locations that are marked
              as covered in the :code:`.coverage` file. If you have a :code:`pytest.ini` that includes
              the :code:`--cov=` command it will automatically generate during the clean-trial run.
        
        
        0.4.2
        -----
        
            - More behind the scenes maintenance: updated debug level logging to include source file
              names and line numbers for all visit operations and separated colorized output to a new
              function.
        
        0.4.1
        -----
        
            - Updated the reporting functions to return colorized display results to CLI.
        
        0.4.0
        -----
        
            - Added new mutation support for:
                1. :code:`AugAssign` in AST e.g. :code:`+= -= *= /=`.
                2. :code:`Index` substitution in lists e.g. take a positive number like :code:`i[1]` and
                   mutate to zero and a negative number e.g. :code:`i[-1] i[0]`.
        
            - Added a :code:`desc` attribute to :code:`transformers.MutationOpSet` that is used in the
              cli help display.
            - Updated the cli help display to show the description and valid members.
        
        0.3.0
        -----
        
            - Added new mutation support for :code:`NameConstant` in AST.
            - This includes substitutions for singleton assignments such as: :code:`True`, :code:`False`,
              and :code:`None`.
            - This is the first non-type mutation and required adding a :code:`readonly` parameter
              to the :code:`transformers.MutateAST` class. Additionally, the type-hints for the
              :code:`LocIndex` and :code:`MutationOpSet` were updated to :code:`Any` to support
              the mixed types. This was more flexible than a series of :code:`overload` signatures.
        
        0.2.0
        -----
        
            - Added new compare mutation support for:
                1. :code:`Compare Is` mutations e.g. :code:`is, is not`.
                2. :code:`Compare In` mutations e.g. :code:`in, not in`.
        
        0.1.0
        -----
        
            - Initial release!
            - Requires Python 3.7 due to the :code:`importlib` internal references for manipulating cache.
            - Run mutation tests using the :code:`mutatest` command line interface.
            - Supported operations:
        
                1. :code:`BinOp` mutations e.g. :code:`+ - / *` including bit-operations.
                2. :code:`Compare` mutations e.g. :code:`== >= < <= !=`.
                3. :code:`BoolOp` mutations e.g. :code:`and or`.
        
        
        Authors
        =======
        
        * Evan Kepner
        
Keywords: mutatest,mutation,testing,test,mutant,mutate
Platform: UNKNOWN
Classifier: Development Status :: 3 - Alpha
Classifier: Intended Audience :: Developers
Classifier: Natural Language :: English
Classifier: Environment :: Console
Classifier: Framework :: Pytest
Classifier: License :: OSI Approved :: MIT License
Classifier: Operating System :: OS Independent
Classifier: Programming Language :: Python :: 3.7
Classifier: Programming Language :: Python :: 3 :: Only
Classifier: Topic :: Software Development :: Libraries :: Python Modules
Classifier: Topic :: Software Development :: Quality Assurance
Classifier: Topic :: Software Development :: Testing
Classifier: Topic :: Software Development :: Testing :: Unit
Requires-Python: >=3.7.0
Provides-Extra: docs
Provides-Extra: tests
Provides-Extra: qa
Provides-Extra: dev
