Coverage.py vs Coverlet
Coverage.py
coverage.readthedocs.ioCoverlet
github.comSide by side
| Figure | Coverage.py | Coverlet |
|---|---|---|
| Price from | Free | Free |
| Free plan | Yes | Yes |
| Free trial | — | — |
| Open source | Yes | — |
| Windows | Yes | Yes |
| macOS | Yes | Yes |
| Linux | Yes | Yes |
| API | Yes | — |
| Self-hosted | Yes | — |
| Plans published | 2 | 1 |
| Spec score · Test Coverage Tools | 8.9 (#2) | 7.7 (#12) |
| Integrations | Official examples cover pytest, unittest, and nose, and pytest commonly uses the pytest-cov plugin. | The project lists a Cake.Coverlet add-in for Cake Build and extensions for viewing coverage in Visual Studio on Windows and Visual Studio for Mac. |
| License | Coverage.py is licensed under the Apache 2.0 License. | The repository states that Coverlet is licensed under the MIT License. |
| Purpose | Coverage.py measures which parts of Python programs ran and identifies executable code that did not run, commonly to gauge test effectiveness. | Coverlet is a cross-platform code coverage framework for .NET with line, branch and method coverage. |
| Report formats | Reports can be emitted as text, HTML, XML, LCOV, or JSON. | The MTP driver supports JSON, LCOV, OpenCover and Cobertura output formats. |
| Support | Users can seek help on the Python discussion forums or Python Discord, report bugs on GitHub, and obtain professional support through Tidelift Subscription. | The project directs users to report bugs and feature requests through the repository’s issues section. |
Plans
In their own words
Coverage.py
Coverage.py measures which parts of Python programs run and highlights executable code that remains untouched, helping developers assess what their tests exercise. It measures statement coverage by default and can also track branch coverage. Reports are available as text, HTML, XML, LCOV, and JSON. Dynamic contexts can associate lines of execution with the test function that ran them. Coverage.py can run test suites through their usual command; pytest-cov is available but the documentation says most users do not need it. Third-party plugins can extend measurement to non-Python files, such as connecting executed Python to Django templates. Data is stored in a SQLite database, and advanced use can rely on its API. The current documentation lists Python 3.10 through 3.15 rc2 and PyPy3 versions 3.10 and 3.11. The tool provides ctrace, pytrace, and sysmon measurement cores; sysmon is faster for simple line and branch coverage but lacks support for dynamic contexts and plugins. Coverage.py is licensed under Apache 2.0 and runs on Linux, macOS, and Windows, with self-hosting available. It is free.
Coverlet
Coverlet is a free, MIT-licensed code coverage framework for modern .NET SDK-style projects. It measures line, branch, and method coverage across Linux, macOS, and Windows. Before tests execute, Coverlet instruments assemblies, records sequence-point hits, restores the original assemblies, and writes coverage results. Drivers are available for Microsoft Testing Platform, the .NET global tool, VSTest, and MSBuild. The Microsoft Testing Platform driver can emit JSON, LCOV, OpenCover, and Cobertura reports. Depending on the driver, teams can merge reports, validate coverage thresholds, and support deterministic builds. Collector and MSBuild packages use VSTest; Microsoft Testing Platform projects instead use coverlet.MTP, which requires the .NET 8.0 SDK or newer. Cake.Coverlet and Visual Studio viewing extensions are also listed. Coverage gates are supported, and bugs or feature requests go through the repository issues section.