pytest is a modern Python testing framework known for its simple syntax and powerful features. It is popular because it requires less boilerplate code, supports fixtures for setup, and has rich plugins.
unittest is Python's built-in testing framework. It uses a class-based approach and requires writing test cases as methods inside test classes.
nose was a testing framework that extended unittest to make testing easier. It is now mostly replaced by pytest and is no longer actively maintained.
pytest automatically finds tests by looking for files and functions starting with test_. unittest requires tests to be inside classes derived from unittest.TestCase.
Because pytest offers simpler syntax, better fixtures, more plugins, and active community support, making tests easier to write and maintain.
unittest is included in Python's standard library, so no extra installation is needed.
pytest uses simple function-based tests and fixtures to reduce boilerplate.
nose is deprecated and replaced by pytest for most use cases.
unittest uses class-based test cases inheriting from unittest.TestCase.
pytest uses simple naming conventions to find tests automatically.