Worker distribution strategies in PyTest - Test Execution Trace

Test Overview

This test checks that pytest distributes test cases evenly across multiple workers when using the pytest-xdist plugin. It verifies that each worker runs a subset of tests and all tests complete successfully.

Test Code - PyTest

PyTest

import pytest

@pytest.mark.parametrize('num', range(6))
def test_sample(num):
    assert num >= 0

# Run command: pytest -n 3
# This runs tests distributed across 3 workers

Execution Trace - 5 Steps

Step	Action	System State	Assertion	Result
1	Test run starts with pytest-xdist plugin enabled using 3 workers	Terminal shows pytest starting with 3 parallel workers	-	PASS
2	Pytest collects 6 test cases from test_sample function	Test collection complete, 6 tests found	Verify total tests collected equals 6	PASS
3	Tests are distributed evenly across 3 workers (2 tests per worker)	Each worker assigned 2 tests to run	Check that each worker runs exactly 2 tests	PASS
4	Each worker executes its assigned tests in parallel	Workers running tests concurrently	Each test assertion (num >= 0) passes	PASS
5	All workers complete tests and report results	Terminal shows all 6 tests passed	Verify all tests passed with no failures	PASS

Failure Scenario

Failing Condition: If pytest-xdist is not installed or workers fail to distribute tests evenly

Execution Trace Quiz - 3 Questions

How many tests does each worker run when using 3 workers for 6 tests?

A 2 tests per worker

B 3 tests per worker

C 6 tests per worker

D 1 test per worker

Key Result

Using pytest-xdist to distribute tests across multiple workers helps run tests faster and ensures workload is balanced, but requires proper plugin installation and configuration.