pytest-clarity
A plugin providing an alternative, colourful diff output for failing assertions.
Decision gist · record as of 2026-08-14
Yes, if you are running pytest on Python 3.6–3.9 and want better visual assertion diffs. The plugin is lightweight, has no dependencies, and is widely downloaded. However, dormancy since 2021 means it may not work with newer pytest or Python versions—verify compatibility with your environment first. If you're on a recent Python or pytest version, test it in a non-critical environment before relying on it.AI-flagged interpretation of the facts on this page — verify before relying
Before you install
- Requires Python 2.7 or 3.6+ (supports 3.6, 3.7, 3.8, 3.9).
- The plugin only activates when pytest is run with the -vv option.
- High install friction: the package is dormant (last release 2021-06-11, last commit 2024-02-18) with no runtime dependencies, but the source distribution requires extraction and installation.
License · maintenance · safety
MIT (permissive) — MIT license (permissive) means you can use, modify, and distribute the package freely with minimal restrictions, provided you include the license notice.
last release 2021-06-11 (1890 days) · last repo commit 2024-02-18 · 455 stars
0 known vulnerabilities (OSV.dev, 2026-08-14) · 650,999 downloads/mo, #5,554 on PyPI
Alternatives
Verify before relying
pip install pytest-clarity
Then run pytest with the -vv flag:
pytest -vv --diff-width=60- Compatibility with pytest versions released after the package's last update (2021-06-11) is unclear.
- Whether the colored diff output works correctly with modern terminal emulators and CI/CD environments.
- Performance impact on large test suites with many failing assertions.
What it is and what it does
pytest-clarity is a pytest plugin that enhances test failure output by replacing the default assertion diff with a colored, side-by-side comparison format inspired by the Ward test framework. When you run pytest with the `-vv` flag, the plugin intercepts failing assertions and renders them with visual highlighting to make differences between expected and actual values easier to spot at a glance.
The plugin requires no runtime dependencies and integrates directly into pytest's output pipeline. It offers two configuration options: `--diff-width` to control the width of the diff display, and `--diff-symbols` to force a symbolic representation instead of colored text. However, the package has been dormant since mid-2021, with no recent commits or releases, so compatibility with very recent pytest or Python versions may not be guaranteed.
Use it for
- Debugging complex assertion failures in test suites where the default pytest diff is hard to read quickly.
- Making test output more readable in CI/CD logs where colored diffs help identify mismatches faster.
- Improving developer experience during local test runs by visually highlighting differences in string, dict, or list comparisons.
- Reducing time spent parsing assertion errors in large test suites with many failing tests.
Worth the install?
AI-flagged interpretation of the facts on this page. Verify before relying on it.
Yes, if you are running pytest on Python 3.6–3.9 and want better visual assertion diffs.
The plugin is lightweight, has no dependencies, and is widely downloaded. However, dormancy since 2021 means it may not work with newer pytest or Python versions—verify compatibility with your environment first. If you're on a recent Python or pytest version, test it in a non-critical environment before relying on it.
Install
pytest-clarity on PyPI
Before you install
High install friction: the package is dormant (last release 2021-06-11, last commit 2024-02-18) with no runtime dependencies, but the source distribution requires extraction and installation. Maintenance status suggests it may not receive updates for compatibility with newer pytest or Python versions.
Requires Python 2.7 or 3.6+ (supports 3.6, 3.7, 3.8, 3.9). The plugin only activates when pytest is run with the -vv option.
License in practice
MIT license (permissive) means you can use, modify, and distribute the package freely with minimal restrictions, provided you include the license notice.
Quickstart
pip install pytest-clarity
Then run pytest with the -vv flag:
pytest -vv --diff-width=60Verify before relying
- Compatibility with pytest versions released after the package's last update (2021-06-11) is unclear.
- Whether the colored diff output works correctly with modern terminal emulators and CI/CD environments.
- Performance impact on large test suites with many failing assertions.
Package facts
| License | MIT permissive |
| Python support | Supports the current Python release >=2.7, !=3.0.*, !=3.1.*, !=3.2.*, !=3.3.* |
| Install friction | High. Source build required |
| Runtime dependencies | None |
| Maintenance | Dormant 1,890 days since the last release |
| Last repo commit | |
| First released | |
| Downloads | 650,999 / month, #5,554 on PyPI 30-day window, as of 2026-08-14 |
| Known vulnerabilities | None known OSV.dev, checked 2026-08-14 |
| Classifiers | Framework :: PytestIntended Audience :: DevelopersLicense :: OSI Approved :: MIT LicenseOperating System :: OS IndependentProgramming Language :: PythonProgramming Language :: Python :: 3.6Programming Language :: Python :: 3.7Programming Language :: Python :: 3.8Programming Language :: Python :: 3.9Programming Language :: Python :: Implementation :: CPythonTopic :: Software Development :: Testing |
Evidence: pytest-clarity-1.0.1.tar.gz
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