tmp_path and tmp_path_factory in PyTest - Test Execution Trace

Test Overview

This test demonstrates how to use tmp_path and tmp_path_factory in pytest to create temporary directories and files. It verifies that files created in these temporary paths exist and contain the expected content.

Test Code - pytest

PyTest

import pytest

# Test using tmp_path fixture

def test_tmp_path_creates_file(tmp_path):
    file = tmp_path / "testfile.txt"
    file.write_text("hello world")
    assert file.exists()
    assert file.read_text() == "hello world"

# Test using tmp_path_factory fixture
@pytest.fixture

def custom_tmp_dir(tmp_path_factory):
    return tmp_path_factory.mktemp("custom")


def test_tmp_path_factory_creates_file(custom_tmp_dir):
    file = custom_tmp_dir / "data.txt"
    file.write_text("pytest tmp_path_factory")
    assert file.exists()
    assert file.read_text() == "pytest tmp_path_factory"

Execution Trace - 9 Steps

Step	Action	System State	Assertion	Result
1	Test starts	pytest test runner initialized	-	PASS
2	pytest injects tmp_path fixture into test_tmp_path_creates_file	Temporary directory created for this test	-	PASS
3	Create file 'testfile.txt' in tmp_path and write 'hello world'	File 'testfile.txt' exists in temporary directory with content 'hello world'	Check file exists	PASS
4	Read file content and assert it equals 'hello world'	File content is 'hello world'	Assert file.read_text() == 'hello world'	PASS
5	pytest injects tmp_path_factory fixture into custom_tmp_dir fixture	Temporary directory 'custom' created by tmp_path_factory	-	PASS
6	custom_tmp_dir fixture returns the 'custom' temporary directory	Test receives custom temporary directory path	-	PASS
7	Create file 'data.txt' in custom_tmp_dir and write 'pytest tmp_path_factory'	File 'data.txt' exists in 'custom' directory with content 'pytest tmp_path_factory'	Check file exists	PASS
8	Read file content and assert it equals 'pytest tmp_path_factory'	File content is 'pytest tmp_path_factory'	Assert file.read_text() == 'pytest tmp_path_factory'	PASS
9	Test ends	All assertions passed, temporary files cleaned up after test	-	PASS

Failure Scenario

Failing Condition: File is not created or content does not match expected string

Execution Trace Quiz - 3 Questions

What does the tmp_path fixture provide in pytest?

A A permanent directory shared across tests

B A temporary directory unique to the test function

C A temporary file only

D A database connection

Key Result

Using tmp_path and tmp_path_factory fixtures in pytest helps create isolated temporary directories for tests, ensuring no leftover files affect other tests and making tests reliable and clean.