pytest-xdist for parallel execution - Test Execution Trace

Test Overview

This test runs multiple simple tests in parallel using pytest-xdist. It verifies that tests execute concurrently and all pass successfully.

Test Code - pytest

PyTest

import pytest
import time

def test_sleep_1():
    time.sleep(1)
    assert True

def test_sleep_2():
    time.sleep(1)
    assert True

def test_sleep_3():
    time.sleep(1)
    assert True

# Run this with: pytest -n 3 test_parallel.py

Execution Trace - 6 Steps

Step	Action	System State	Assertion	Result
1	Test runner starts with pytest-xdist using 3 workers	pytest-xdist initializes 3 parallel workers	-	PASS
2	Worker 1 runs test_sleep_1, sleeps 1 second	test_sleep_1 is executing in worker 1	-	PASS
3	Worker 2 runs test_sleep_2, sleeps 1 second	test_sleep_2 is executing in worker 2	-	PASS
4	Worker 3 runs test_sleep_3, sleeps 1 second	test_sleep_3 is executing in worker 3	-	PASS
5	Each test asserts True after sleep	All tests completed their sleep and assertion	assert True is True for all tests	PASS
6	pytest-xdist collects results from all workers	Test results aggregated	All tests passed	PASS

Failure Scenario

Failing Condition: One or more tests fail their assertion or worker crashes

Execution Trace Quiz - 3 Questions

What does pytest-xdist do in this test?

A Skips tests that take longer than 1 second

B Runs tests sequentially in one process

C Runs tests in parallel using multiple workers

D Runs tests only on a single CPU core

Key Result

Using pytest-xdist allows running tests in parallel, which speeds up test execution especially when tests are independent and involve waiting or delays.