coincidence.regressions

Regression test helpers.

To enable the fixtures in this module add the following to conftest.py in your test directory:

pytest_plugins = ("coincidence", )

Classes:

AdvancedDataRegressionFixture(datadir, …)	Subclass of DataRegressionFixture with support for additional types.
AdvancedFileRegressionFixture(datadir, …)	Subclass of FileRegressionFixture with UTF-8 by default and some extra methods.
SupportsAsDict	typing.Protocol for classes like collections.namedtuple() and typing.NamedTuple which implement an _asdict() method.

Functions:

advanced_data_regression(datadir, …)	Pytest fixture for performing regression tests on lists, dictionaries and namedtuples.
advanced_file_regression(datadir, …)	Pytest fixture for performing regression tests on strings, bytes and files.
check_file_regression(data, file_regression)	Check the given data against that in the reference file.
check_file_output(filename, file_regression)	Check the content of the given text file against the reference file.

class AdvancedDataRegressionFixture(datadir, original_datadir, request)

Bases: DataRegressionFixture

Subclass of DataRegressionFixture with support for additional types.

The following types and their subclasses are supported:

• collections.abc.Mapping, typing.Mapping (including dict and typing.Dict)

• collections.abc.Sequence, typing.Sequence (including list, typing.Tuple etc.)

• collections.OrderedDict, typing.OrderedDict

• collections.Counter, typing.Counter

• types.MappingProxyType (cannot be subclassed)

• _pytest.capture.CaptureResult (the type of capsys.readouterr())

• Any type which implements the SupportsAsDict protocol (including collections.namedtuple() and typing.NamedTuple)

check(data_dict, basename=None, fullpath=None)

Checks data against a previously recorded version, or generates a new file.

Parameters

• data_dict (Union[Sequence, SupportsAsDict, Mapping, MappingProxyType, CaptureResult])

• basename (Optional[str]) – The basename of the file to test/record. If not given the name of the test is used. Default None.

• fullpath (Optional[str]) – The complete path to use as a reference file. This option will ignore datadir fixture when reading expected files, but will still use it to write obtained files. Useful if a reference file is located in the session data dir, for example. Default None.

Note

basename and fullpath are exclusive.

class AdvancedFileRegressionFixture(datadir, original_datadir, request)

Bases: FileRegressionFixture

Subclass of FileRegressionFixture with UTF-8 by default and some extra methods.

New in version 0.2.0.

Methods:

check(contents[, encoding, extension, …])	Checks the contents against a previously recorded version, or generates a new file.
check_bytes(contents, **kwargs)	Checks the bytes contents against a previously recorded version, or generates a new file.
check_file(filename[, extension, newline])	Check the content of the given text file against the reference file.

check(contents, encoding='UTF-8', extension='.txt', newline=None, basename=None, fullpath=None, binary=False, obtained_filename=None, check_fn=None)

Checks the contents against a previously recorded version, or generates a new file.

Parameters

• contents (Union[str, StringList])

• extension (str) – The extension of the reference file. Default '.txt'.

• **kwargs – Additional keyword arguments passed to pytest_regressions.file_regression.FileRegressionFixture.check().

See also

check_file_regression()

check_bytes(contents, **kwargs)

Checks the bytes contents against a previously recorded version, or generates a new file.

Parameters

• contents (bytes)

• **kwargs – Additional keyword arguments passed to pytest_regressions.file_regression.FileRegressionFixture.check().

check_file(filename, extension=None, newline='\n', **kwargs)

Check the content of the given text file against the reference file.

Parameters

• filename (Union[str, Path, PathLike])

• extension (Optional[str]) – The extension of the reference file. If None the extension is determined from filename. Default None.

• newline (Optional[str]) – Controls how universal newlines mode works. See open(). Default '\n'.

• **kwargs – Additional keyword arguments passed to pytest_regressions.file_regression.FileRegressionFixture.check().

See also

check_file_output()

protocol SupportsAsDict

Bases: Protocol

typing.Protocol for classes like collections.namedtuple() and typing.NamedTuple which implement an _asdict() method.

This protocol is runtime checkable.

Classes that implement this protocol must have the following methods / attributes:

_asdict()

Return a new dict which maps field names to their corresponding values.

Return type

Dict[str, Any]

fixture advanced_data_regression

Scope:    function

Pytest fixture for performing regression tests on lists, dictionaries and namedtuples.

Return type

AdvancedDataRegressionFixture

fixture advanced_file_regression

Scope:    function

Pytest fixture for performing regression tests on strings, bytes and files.

New in version 0.2.0.

Return type

AdvancedFileRegressionFixture

check_file_regression(data, file_regression, extension='.txt', **kwargs)

Check the given data against that in the reference file.

Parameters

• data (Union[str, StringList])

• file_regression (FileRegressionFixture) – The file regression fixture for the test.

• extension (str) – The extension of the reference file. Default '.txt'.

• **kwargs – Additional keyword arguments passed to pytest_regressions.file_regression.FileRegressionFixture.check().

See also

AdvancedFileRegressionFixture.check()

Return type

bool

check_file_output(filename, file_regression, extension=None, newline='\n', **kwargs)

Check the content of the given text file against the reference file.

Parameters

• filename (Union[str, Path, PathLike])

• file_regression (FileRegressionFixture) – The file regression fixture for the test.

• extension (Optional[str]) – The extension of the reference file. If None the extension is determined from filename. Default None.

• newline (Optional[str]) – Controls how universal newlines mode works. See open(). Default '\n'.

• **kwargs – Additional keyword arguments passed to pytest_regressions.file_regression.FileRegressionFixture.check().

See also

AdvancedFileRegressionFixture.check_file()

Return type

bool