Custom markers in PyTest - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a custom marker in pytest?

A custom marker is a label you create to tag tests for special handling, like grouping or skipping them during test runs.

beginner

How do you define a custom marker in pytest?

You define a custom marker by adding it to the pytest.ini file under the [pytest] section using the markers option.

beginner

How do you apply a custom marker to a test function?

Use the @pytest.mark.<marker_name> decorator above the test function to apply the custom marker.

beginner

What command runs only tests with a specific custom marker?

Use pytest -m '<marker_name>' to run only tests tagged with that custom marker.

intermediate

Why should you register custom markers in pytest.ini?

Registering markers avoids warnings and helps pytest recognize your custom tags properly.

How do you mark a test with a custom marker named 'slow'?

A @pytest.mark.slow

B @slow

C mark('slow')

D pytest.mark('slow')

Use the decorator @pytest.mark.slow to apply the 'slow' marker to a test.

Where do you register custom markers to avoid warnings?

A test file header

B conftest.py

C setup.py

D pytest.ini

Custom markers should be registered in pytest.ini under the [pytest] section.

What does the command 'pytest -m slow' do?

A Skips tests marked with 'slow'

B Runs only tests marked with 'slow'

C Runs all tests except those marked 'slow'

D Runs tests with names containing 'slow'

The -m option runs only tests that have the specified marker.

What happens if you use a custom marker without registering it?

A Tests run but marker is ignored silently

B Tests fail to run

C Pytest shows a warning about unknown markers

D Pytest crashes

Pytest warns about unknown markers if they are not registered.

Which file is best for defining markers used across many test files?

A pytest.ini

B test_example.py

C requirements.txt

D README.md

pytest.ini is the central place to register markers for all tests.

Explain how to create and use a custom marker in pytest.

Think about registration, tagging, and running tests.

Why is it important to register custom markers in pytest.ini?

Consider what happens if you don't register.