conftestpy

Conftest.py is a special configuration and fixture file used by the Python testing framework pytest. It is named conftest.py by convention and is automatically discovered by pytest in test directories, helping to share fixtures and hooks across tests without importing them explicitly. Some users colloquially refer to the concept as conftestpy, but the official file name remains conftest.py.

Pytest loads conftest.py files from a test directory and all its parent directories, making the fixtures and hooks defined there available to tests within that directory tree. This hierarchical loading enables centralized setup and utilities that can be reused across many test modules, while preserving directory-level scope boundaries. Fixtures defined in conftest.py can be used by any test function or by other fixtures simply by declaring them as parameters.

Fixtures in conftest.py support common features such as scope (function, class, module, session), parameterization, and autouse. A fixture can depend on other fixtures by listing them as parameters, and fixtures can use yield to provide a setup and teardown sequence. In addition to fixtures, conftest.py can implement pytest hook functions (for example pytest_configure or pytest_collection_modifyitems) to customize test collection, configuration, or execution.

Best practices include keeping conftest.py lightweight, documenting fixtures, and avoiding heavy imports to minimize test startup time. While conftest.py is a central place for test setup, it should not duplicate logic better placed in plugins or individual test modules. In summary, conftest.py is a core pytest mechanism for sharing fixtures and lifecycle hooks across a test suite.