tmp_path

Pytest · Reference cheat sheet

📋 Overview

tmp_path and tmp_path_factory give per-test (or session) temporary directories as pathlib.Path. Prefer them over manual tempfile cleanup.

🔧 Core concepts

Fixture	Scope
`tmp_path`	Unique dir per test function
`tmp_path_factory`	Create extra dirs; session-friendly
`tmpdir`	Legacy py.path — prefer `tmp_path`
basetemp	`--basetemp=` keeps dirs for debug

pytest cleans default temp roots between runs unless basetemp is set.

💡 Examples

Write files:

def test_config(tmp_path):
    cfg = tmp_path / "config.toml"
    cfg.write_text('[app]\nname = "demo"\n', encoding="utf-8")
    assert "demo" in cfg.read_text(encoding="utf-8")

Nested layout:

def test_project(tmp_path):
    src = tmp_path / "src"
    src.mkdir()
    (src / "main.py").write_text("print(1)\n", encoding="utf-8")
    assert (tmp_path / "src" / "main.py").exists()

Factory (session):

import pytest

@pytest.fixture(scope="session")
def dataset_dir(tmp_path_factory):
    root = tmp_path_factory.mktemp("data")
    (root / "sample.csv").write_text("a,b\n1,2\n", encoding="utf-8")
    return root

Keep on failure:

pytest --basetemp=./.pytest-tmp

⚠️ Pitfalls

Storing secrets in tmp dirs on shared CI runners.
Assuming tmp_path survives across tests — it does not.
Using string paths with APIs that need Path or vice versa.
Parallel xdist workers — each has isolated temps; don't hardcode shared paths.
Preferring tmpdir in new code (deprecated style).

tmp_path

tmp_path

📋 Overview

🔧 Core concepts

💡 Examples

⚠️ Pitfalls

🔗 Related

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