if an autouse fixture is defined in a test module, all its test functions automatically use it. scope='class' means it will be run once per class, etc. There are many, many nuances to fixtures (e.g. Let's look at a simple test module that contains a fixture and a test case that uses it: Also flake8 checks will complain about unknown methods in parameters (it's minor issue, but it's still exists). This article demonstrates alternatives way for an easier migration, with the following benefits: db = DummyDB () fixture (scope = "class") def db_class (request): class DummyDB: pass # set a class attribute on the invoking test context request. I'm running Pytest 3.2.5 with Python 3. The Problem What exactly is the problem I’ll be describing: using pytest to share the same instance of setup and teardown code among multiple tests. If a fixture is used in the same module in which it is defined, the function name of the fixture will be shadowed by the function arg that requests the fixture; one way to resolve this is to name the decorated function fixture_ and then use @pytest.fixture(name=''). Package/Directory-level fixtures (setups)¶ If you have nested test directories, you can have per-directory fixture scopes by placing fixture functions in a conftest.py file in that directory You can use all types of fixtures including autouse fixtures which are the equivalent of xUnit’s setup/teardown concept. def test_one(): obj.do_something_fancy() The test case can accept the name of fixture as an input parameter, which is the return value of the corresponding fixture function. For example you can do something like this (via @imiric): Fixtures are a powerful feature of PyTest. # content of conftest.py # we define a fixture function below and it will be "used" by # referencing its name from tests import pytest @pytest. But when I apply also a fixture with scope "function", that seems to affect also the "class" fixture. cls. The tmp_path_factory fixture¶ The tmp_path_factory is a session-scoped fixture which can be used to create arbitrary temporary directories from any other fixture or test. Although my original answer (below) was the only way to do this in older versions of pytest as others have noted pytest now supports indirect parametrization of fixtures. Although I’d love to write a small article detailing an easy introduction to pytest, I’d be digressing from the original title. I basically want to apply a fixture with scope "class" but parametrizing the fixture. I’ve been using pytest for writing tests because I absolutely love the simple assert systems. The return value of fixture1 is passed into test_add as an argument with a name fixture1. This defaults to the name of the decorated function. Migration from unittest-style tests with setUp methods to pytest fixtures can be laborious, because users have to specify fixtures parameters in each test method in class. It is intended to replace tmpdir_factory, and returns pathlib.Path instances. A fixture can be registered with the @pytest.fixture decorator. if an autouse fixture is defined in a conftest.py file then all tests in all test modules below its directory will invoke the fixture. Fixtures help us to setup some pre-conditions like setup a database connection / get test data from files etc that should run before any tests are executed. The idea is to have groups of tests defined by classes, and to run those groups with different configurations. Earlier we have seen Fixtures and Scope of fixtures, In this article, will focus more on using fixtures with conftest.py We can put fixtures into individual test files, if we want @pytest.fixture(scope='session', autouse=True) def setup_func(request): obj = SomeObj() Next thing, I want some magic that previously created obj will appear in each test context without the need of each test to define the setup_func fixture. @pytest.fixture def fixture1(): return "Yes" def test_add(fixture1): assert fixture1 == "Yes" In this example fixture1 is called at the moment of execution of test_add. See tmp_path_factory API for details. Use Case. Update: Since this the accepted answer to this question and still gets upvoted sometimes, I should add an update. Registered with the @ pytest.fixture decorator directory will invoke the fixture about unknown methods parameters. Something like this ( via @ imiric ): this defaults to the of! 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