Temporary directory management in PyTest - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the purpose of using a temporary directory in pytest tests?

A temporary directory provides a safe, isolated space to create files or folders during tests without affecting the real file system. It is automatically cleaned up after the test finishes.

beginner

How do you access a temporary directory in a pytest test function?

You use the built-in pytest fixture called tmp_path or tmpdir. Just add it as a parameter to your test function, and pytest provides a fresh temporary directory path.

intermediate

What is the difference between tmp_path and tmpdir fixtures in pytest?

tmp_path returns a pathlib.Path object, which is modern and recommended. tmpdir returns a py.path.local object, which is older. Both create temporary directories.

beginner

Why is it important that pytest cleans up the temporary directory after the test?

Cleaning up prevents leftover files from filling disk space or interfering with other tests. It keeps tests independent and the environment clean.

beginner

Show a simple pytest test function that writes a file in a temporary directory using tmp_path.

import pytest

def test_write_file(tmp_path):
    file = tmp_path / "test.txt"
    file.write_text("hello")
    assert file.read_text() == "hello"

Which pytest fixture provides a temporary directory as a pathlib.Path object?

A tmp_path

B tmpdir

C tempfile

D temp_dir

tmp_path returns a pathlib.Path object for temporary directories. tmpdir returns a py.path.local object.

What happens to the temporary directory created by pytest after the test finishes?

A It remains on disk until manually deleted

B It is deleted automatically

C It is moved to a backup folder

D It is archived as a zip file

pytest automatically cleans up temporary directories after tests to keep the environment clean.

Why should tests use temporary directories instead of real folders?

A To permanently save test data

B To speed up test execution

C To share files between tests

D To avoid affecting real files and keep tests isolated

Temporary directories isolate test data and prevent side effects on real files.

Which of these is NOT a pytest fixture for temporary directories?

A tmp_path

B tempfile

C tmp_file

D tmpdir

tmp_file is not a pytest fixture. tmp_path and tmpdir are valid fixtures.

In pytest, how do you write text to a file inside a temporary directory using tmp_path?

A file = tmp_path / 'file.txt'; file.write_text('data')

B file = tmp_path.join('file.txt'); file.write('data')

C file = tmp_path.create_file('file.txt'); file.write('data')

D file = tmp_path.open('file.txt'); file.write('data')

tmp_path uses pathlib.Path syntax: use / to join paths and write_text() to write text.

Explain how pytest's temporary directory fixtures help keep tests independent and clean.

Think about why tests should not share or keep files after running.

Describe the difference between pytest's tmp_path and tmpdir fixtures and when to prefer one over the other.

Consider the Python standard library's pathlib module.