pytest-diff

=========== pytest-diff

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A simple plugin to use with pytest

This pytest_ plugin was generated with Cookiecutter_ along with @hackebrot's cookiecutter-pytest-plugin template.

Features

• Readable diffs for failed tests
• Customizable diffs for your classes

Requirements

• pytest
• deepdiff
• pprintpp

Installation

You can install "pytest-diff" via pip_ from PyPI_::

$ pip install pytest-diff

Usage

.. code-block:: python

class Person:
    def __init__(self, name, age, favorites):
        self.name = name
        self.age = age
        self.favorites = favorites


def test_person():
    a = Person("Alice", age=21, favorites={"food": "spam", "movie": "Life of Brian"})
    b = Person("Alice", age=21, favorites={"food": "eggs", "movie": "Life of Brian"})
    assert a == b

Running :code:pytest gives:

.. code-block:: python

______________________________ test_person ______________________________

    def test_person():
        a = Person("Alice", age=21, favorites={'food': 'spam', 'movie': 'Life of Brian'})
        b = Person("Alice", age=21, favorites={'food': 'eggs', 'movie': 'Life of Brian'})
>       assert a == b
E       assert
E         <test_person.Person object at 0x7fa326d769e8>
E         ==
E         <test_person.Person object at 0x7fa326d76be0>
E         {'values_changed': {"root.favorites['food']": {'new_value': 'spam', 'old_value': 'eggs'}}}

examples/test_person.py:11: AssertionError

To customize diffs for a specific type, register it with the registry:

.. code-block:: python

import pytest_diff


class Car:
    def __init__(self, make, model, year):
        self.make = make
        self.model = model
        self.year = year


@pytest_diff.registry.register(Car)
def diff(x, y):
    return [
               f"{x.make} vs {y.make}",
               f"{x.model} vs {y.model}",
               f"{x.year} vs {y.year}",
           ]


def test_car():
    c1 = Car("Toyota", "Prius", 2010)
    c2 = Car("Honda", "Accord", 2009)
    assert c1 == c2

Then running :code:pytest shows your custom diff:

.. code-block:: python

    def test_car():
        c1 = Car("Toyota", "Prius", 2010)
        c2 = Car("Honda", "Accord", 2009)
>       assert c1 == c2
E       assert
E         <test_custom.Car object at 0x7f0e9b0ccd68>
E         ==
E         <test_custom.Car object at 0x7f0e9b0cceb8>
E         Toyota vs Honda
E         Prius vs Accord
E         2010 vs 2009

examples/test_custom.py:21: AssertionError

Contributing

Contributions are very welcome. Tests can be run with tox_, please ensure the coverage at least stays the same before you submit a pull request.

License

Distributed under the terms of the MIT_ license, "pytest-diff" is free and open source software

Issues

If you encounter any problems, please file an issue_ along with a detailed description.

.. _Cookiecutter: https://github.com/audreyr/cookiecutter .. _@hackebrot: https://github.com/hackebrot .. _MIT: http://opensource.org/licenses/MIT .. _BSD-3: http://opensource.org/licenses/BSD-3-Clause .. _GNU GPL v3.0: http://www.gnu.org/licenses/gpl-3.0.txt .. _Apache Software License 2.0: http://www.apache.org/licenses/LICENSE-2.0 .. _cookiecutter-pytest-plugin: https://github.com/pytest-dev/cookiecutter-pytest-plugin .. _file an issue: https://github.com/username/pytest-diff/issues .. _pytest: https://github.com/pytest-dev/pytest .. _tox: https://tox.readthedocs.io/en/latest/ .. _pip: https://pypi.org/project/pip/ .. _PyPI: https://pypi.org/project