Pytest and unittest are two popular testing frameworks for Python. Pytest is known for its simplicity, scalability, and powerful features such as fixture support and parameterization. It has a concise syntax and a rich plugin ecosystem. On the other hand, unittest is a built-in testing framework that follows the xUnit style and is part of the Python Standard Library. It has features such as test discovery, fixture support, and test suites. Pytest offers advantages like automatic test discovery, skip/xfail tests, and powerful assertion introspection. It also supports parallel test execution and offers easy mocking and patching. However, it is not part of the Python Standard Library and may have a moderate learning curve for beginners.

Unittest, being part of the Python Standard Library, has the advantage of widespread adoption and being a community standard. It has features like test discovery, fixture support, and consistent test isolation. However, it has a more verbose syntax and limited parameterization support. When choosing between pytest and unittest, consider factors like project requirements, team preferences, and the complexity of testing scenarios. PyCharm offers support and integration for both frameworks, providing features like intelligent code completion, test discovery, debugging, and result visualization. Ultimately, the choice depends on your specific needs and development philosophy.