Running tests by marker (-m) in PyTest

Introduction

Markers help you group tests by labels. Running tests by marker lets you run only specific groups of tests quickly.

You want to run only fast tests before a quick check.

You want to run tests related to a specific feature only.

You want to skip slow tests during development.

You want to run tests that require a database separately.

You want to run tests marked as 'smoke' before deployment.

Syntax

PyTest

pytest -m <marker_name>

Replace <marker_name> with the label you assigned to tests.

You can combine markers with 'and', 'or', 'not' for complex selection.

Examples

Runs only tests marked with @pytest.mark.smoke.

PyTest

pytest -m smoke

Runs tests marked as 'slow' or 'database'.

PyTest

pytest -m "slow or database"

Runs all tests except those marked 'slow'.

PyTest

pytest -m "not slow"

Sample Program

This test file has three tests. Two are marked 'smoke' and one is marked 'slow'.

Running pytest -m smoke will run only the two smoke tests.

PyTest

import pytest

@pytest.mark.smoke
def test_login():
    assert True

@pytest.mark.slow
def test_data_processing():
    assert True

@pytest.mark.smoke
def test_logout():
    assert True

Important Notes

Markers must be registered in pytest.ini or you get warnings.

Use quotes around marker expressions with spaces or operators.

Markers help organize tests and speed up running only what you need.

Summary

Markers label tests for easy grouping.

Use pytest -m <marker> to run tests with that label.

You can combine markers with logical operators for flexible test selection.