Coverage.py vs OpenClover

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.

OpenClover is a free code coverage tool for Java, Groovy and AspectJ. It tracks global, per-test and distributed per-test coverage using method, statement and branch metrics. More than 20 built-in code metrics are included, and custom metrics are supported. Coverage reports can be generated as HTML, XML, PDF, JSON or text. You can narrow coverage scope by paths, classes, methods, code blocks, statements, complexity or inline comments. For test optimization, OpenClover identifies tests to rerun when classes change, can run failing tests first, and can randomize test order. Integrations include Ant, Maven, Gradle, Grails, Griffon, Jenkins, Bamboo, Eclipse, IntelliJ IDEA, Sonar and JIRA. Dedicated test support covers JUnit 3 and 4, TestNG and Spock. Version 5.1.x supports JRE or JDK 8 through 25 and Groovy 3.x, 4.x and 5.x. The project is volunteer-maintained and Apache 2.0 licensed; community support typically responds within a few days.