Verify pytest marker registration and usage

Preconditions (2)

Step 1: Create a test file test_sample.py

Step 2: Add a test function test_example marked with @pytest.mark.smoke

Step 3: Run pytest with the -m smoke option to select tests with the smoke marker

✅ Expected Result: Only the test_example function runs and passes without marker warnings

Automation Requirements - pytest

Assertions Needed:

Verify test_example runs when using -m smoke

Verify no warnings about unregistered markers appear

Best Practices:

Use @pytest.mark.<marker_name> decorator

Use pytest command line option -m to select tests by marker

Avoid hardcoding marker names in test code

Automated Solution

PyTest

import subprocess
import sys
import pytest

# pytest.ini content to register marker
pytest_ini_content = """
[pytest]
markers =
    smoke: mark a test as smoke test
"""

# Write pytest.ini file
with open('pytest.ini', 'w') as f:
    f.write(pytest_ini_content)

# test_sample.py content
test_code = '''
import pytest

@pytest.mark.smoke

def test_example():
    assert True
'''

with open('test_sample.py', 'w') as f:
    f.write(test_code)

# Run pytest with -m smoke
result = subprocess.run([sys.executable, '-m', 'pytest', '-m', 'smoke', '--tb=short', '-q'], capture_output=True, text=True)

# Check output for test run and no warnings
assert 'test_example' in result.stdout, 'test_example did not run'
assert 'WARNING' not in result.stdout, 'Found warnings about markers'
assert result.returncode == 0, f'Pytest failed with code {result.returncode}'

print('Test passed: marker registration and usage works correctly')

This script automates the verification of pytest marker registration.

First, it creates a pytest.ini file registering the smoke marker to avoid warnings.

Then it writes a test file test_sample.py with a test function marked with @pytest.mark.smoke.

It runs pytest with the -m smoke option to select only tests with the smoke marker.

Assertions check that the test ran, no warnings about markers appeared, and pytest exited successfully.

This approach ensures the marker is properly registered and used, following best practices.

Common Mistakes - 4 Pitfalls

Not registering custom markers in pytest.ini

Using marker names inconsistently or misspelling them

Hardcoding marker names in test code without registration

Running pytest without the -m option to select markers

Bonus Challenge

Now add data-driven testing with 3 different test functions each marked with different custom markers registered in pytest.ini

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