Coverage.py vs Istanbul
Coverage.py
coverage.readthedocs.ioIstanbul
istanbul.js.orgSide by side
| Figure | Coverage.py | Istanbul |
|---|---|---|
| Price from | Free | — |
| Free plan | Yes | — |
| Free trial | — | — |
| Open source | Yes | — |
| Windows | Yes | — |
| macOS | Yes | — |
| Linux | Yes | — |
| API | Yes | Yes |
| Self-hosted | Yes | — |
| Plans published | 2 | 0 |
| Spec score · Test Coverage Tools | 8.9 (#2) | 6.9 (#23) |
| Integrations | Official examples cover pytest, unittest, and nose, and pytest commonly uses the pytest-cov plugin. | Listed integrations are nyc, c8, Jest and node-tap; c8 uses Istanbul reports to display V8 coverage. |
| License | Coverage.py is licensed under the Apache 2.0 License. | The Istanbul site identifies its license as Revised BSD License. |
| Purpose | Coverage.py measures which parts of Python programs ran and identifies executable code that did not run, commonly to gauge test effectiveness. | Istanbul instruments JavaScript code with line counters to track how well unit tests exercise a codebase. |
| Reports | It can produce text, HTML, XML, LCOV, and JSON reports. | Istanbul provides reporters with terminal and HTML output. |
| 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 contributing page directs users to report bugs by opening an issue in the appropriate GitHub repository. |
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.