pytest 'fixture 'xyz' not found' (E fixture 'xyz' not found, available fixtures: ...): why can't pytest see my fixture and how do I fix it?

Cause: pytest only injects fixtures that are visible from the test's location. A fixture is visible to tests in the same module (or class, if defined in a class), and to tests in the directory of a conftest.py and everything beneath it. Lookup goes upward through enclosing directories, never into sibling or child directories, and installed plugins are searched last. The error means no fixture with that exact name is reachable: typo in the name, the fixture lives in a different test module or sibling directory, conftest.py is in the wrong folder or misnamed, the plugin that provides it (pytest-mock, pytest-asyncio and so on) is not installed in the active environment, or the function lacks the @pytest.fixture decorator. Fix (best first): 1. Run pytest --fixtures path/to/test_file.py (add -v to see names starting with an underscore). The error message also lists the available fixtures. Compare spelling. 2. Move shared fixtures into a conftest.py placed in the common parent directory of the tests that use them; no import is needed. Make sure the file is spelled exactly conftest.py. 3. Confirm the decorator: @pytest.fixture (with parentheses allowed). A plain function with the right name is just a function. 4. If the fixture comes from a plugin, install it in the same environment that runs pytest (python -m pytest, pip show <plugin>) and check pytest --version output lists the plugin. 5. To share fixtures from a regular module, register it as a plugin with pytest_plugins = ["myproject.fixtures"] in the top-level conftest.py. The pytest docs discourage importing fixture functions into test modules, as this is fragile. 6. For unittest-style classes, fixtures cannot be passed as method arguments; use @pytest.mark.usefixtures("name") or autouse fixtures instead. Verify: pytest --fixtures path/to/test_file.py lists the fixture, and the test runs with the fixture value injected. Sources: https://docs.pytest.org/en/stable/how-to/fixtures.html https://docs.pytest.org/en/stable/reference/fixtures.html