A plugin to improve the output of pytest with colourful unified diffs
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Latest commit a46c4ff Oct 19, 2018



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A plugin to improve the readability of pytest output.


  • Enables an easier to parse and more understandable diff for your failing tests.
  • Can display unified diffs or split diffs, and chooses them depending on the context.
  • Adds helpful hints to the output for failing tests to help you track down common issues.

With pytest-clarity:

Example output with clarity

The same test, without pytest-clarity:

Example output without clarity


Supports Python 2.7 and 3.4+


You can install "pytest-clarity" via pip from PyPI:

$ pip install pytest-clarity


Install the plugin as described above, and it will be automatically enabled.

You can choose which type of diff you want with --diff-type (auto (default), split or unified):

pytest --diff-type=split

You can disable hints using the --no-hints flag:

pytest --no-hints

You can configure the width of the output with the --diff-width option:

pytest --diff-width=60


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.


Distributed under the terms of the MIT license, "pytest-clarity" is free and open source software.


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

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