Test infrastructure

Ensures tests have isolated, automatically-cleaned temporary directories with custom naming prefixes

Test suites: needing a custom-named temp directory fixture shared across multiple tests; Integration tests: requiring a specific directory structure under a temporary path; Plugin development: providing a reusable temp directory fixture with a meaningful prefix

pytest, test automation, CI/CD pipelines, conftest.py files

@pytest.fixture def fixture_name(tmp_path_factory): return tmp_path_factory.mktemp(prefix)

@pytest.fixture def ...(...): return ....mktemp(...)

fixture_name: valid Python identifier for the fixture, prefix: str naming the temporary directory

• tmp_path
• tmp_path_factory
• conftest.py
• pytest.fixture
• pathlib.Path

• tmp_path fixture (built-in
• per-test directory without custom prefix
• simpler but less control)
• tmpdir fixture (legacy py.path-based
• deprecated in favor of tmp_path)
• tempfile.mkdtemp() (stdlib
• requires manual cleanup and no pytest integration)

1. Using tmp_path instead of tmp_path_factory when a custom prefix is needed — tmp_path ignores custom naming, leading to generic directory names. 2. Forgetting the @pytest.fixture decorator — the function becomes a plain helper and cannot be injected into tests. 3. Returning a string instead of the pathlib.Path object — downstream code expecting Path methods like / operator will fail with AttributeError. 4. Using tmpdir_factory (legacy) instead of tmp_path_factory — returns py.path.local objects incompatible with pathlib-based code.

tmp_path fixture (per-test auto-named directory, no prefix control); tmp_path_factory.mktemp with basedir parameter (controls parent directory location); tempfile.TemporaryDirectory context manager (stdlib, requires explicit cleanup)

Coming from unittest: may use tempfile.mkdtemp() and manual cleanup — pytest's tmp_path_factory handles cleanup automatically after the test session ends.

• pytest fixtures
• tmp_path
• tmp_path_factory
• conftest.py fixtures
• test isolation

Do not use when tmp_path alone suffices for simple per-test temp directories — tmp_path_factory.mktemp adds unnecessary complexity for the common case. The returned path is a pathlib.Path object, not a string, so str() conversion may be needed for legacy APIs. The directory is created immediately on disk; there is no lazy creation.

Eliminates manual temporary directory cleanup code and prevents cross-test contamination by providing unique, automatically-managed directories

Like renting a labeled hotel room for your test data — it's ready when you arrive, tagged with your name, and housekeeping cleans it up at checkout.

tmp_path_factory is session-scoped by default, so directories created via mktemp persist for the entire test session. For per-test isolation, prefer the tmp_path fixture instead.

Session-scoped fixtures with tmp_path_factory, parametrized fixture factories, fixture scoping (scope='session')