Registering markers in pytest.ini - Practice Problems & Coding Challenges

Challenge - 5 Problems

🧠 Conceptual

intermediate

Purpose of registering markers in pytest.ini

Why is it important to register custom markers in the pytest.ini file when using pytest?

A To automatically run all tests without specifying any marker

B To disable all tests that do not have a marker

C To avoid warnings about unknown markers and enable filtering tests by those markers

D To change the default test discovery pattern

💡 Hint

Think about what happens if you use a marker that pytest does not recognize.

Registering markers in pytest.ini tells pytest about your custom markers. This prevents warnings and allows you to select tests by marker using command line options.

❓ Predict Output

intermediate

Output when using unregistered marker

What warning or error will pytest show when running tests with an unregistered custom marker?

PyTest

[test_sample.py]
import pytest

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

# pytest.ini does NOT register 'slow' marker

A WARNING: Unknown pytest.mark.slow - is this a typo? You can register markers in pytest.ini

B ERROR: Marker 'slow' not found. Test run aborted.

C No warnings or errors, test runs normally

D SyntaxError: invalid marker usage

💡 Hint

Think about pytest's behavior when it sees a marker it does not know.

Pytest shows a warning about unknown markers if they are not registered in pytest.ini but still runs the tests.

❓ locator

advanced

Correct pytest.ini marker registration syntax

Which of the following is the correct way to register a custom marker named database in pytest.ini?

A

[pytest]
markers = database; mark tests that require database access

B

[pytest]
markers = database - mark tests that require database access

C

[pytest]
markers = database # mark tests that require database access

D

[pytest]
markers = database: mark tests that require database access

💡 Hint

Look for the correct syntax for comments in pytest.ini under markers.

The correct syntax uses a colon ':' after the marker name followed by a description. Other separators cause parsing errors or are ignored.

❓ assertion

advanced

Assertion to check marker registration effect

Given the following pytest.ini and test code, which assertion correctly verifies that the api marker is registered and can be used to select tests?

PyTest

[pytest.ini]
[pytest]
markers = api: mark tests as API tests

[test_api.py]
import pytest

@pytest.mark.api
def test_api_call():
    assert True

A assert 'api' in pytest.markers

B assert any(m.startswith('api:') for m in pytest.config.getini('markers'))

C assert 'api' in pytest.ini

D assert pytest.mark.api is not None

💡 Hint

Think about how pytest exposes ini options in code.

The correct way to check registered markers programmatically is to access pytest.config.getini('markers') which returns a list of registered markers.

❓ framework

expert

Effect of missing marker registration on test selection

If a custom marker integration is used in tests but NOT registered in pytest.ini, what happens when you run pytest -m integration?

A Pytest shows a warning about unknown marker but runs tests with the integration marker

B Pytest runs all tests ignoring the marker filter

C Pytest raises an error and aborts the test run

D Pytest runs only tests with the integration marker without warnings

💡 Hint

Consider how pytest handles unknown markers during test selection.

Pytest warns about unknown markers but when filtering with -m for an unregistered marker, it still selects and runs the matching tests.

Practice

1. What is the main purpose of registering markers in the pytest.ini file?

easy

A. To define test data inputs for parameterized tests

B. To organize tests and avoid warnings about unknown markers

C. To automatically generate test reports

D. To speed up test execution by caching results

Solution

1. Step 1: Understand marker registration purpose

   Markers are labels for tests that help organize and select tests to run.

2. Step 2: Recognize why registration is needed

   Registering markers in pytest.ini prevents warnings about unknown markers and keeps tests organized.

3. Final Answer:

   To organize tests and avoid warnings about unknown markers -> Option B

4. Quick Check:

   Marker registration = organize tests + avoid warnings [OK]

Hint: Markers in pytest.ini prevent warnings and organize tests [OK]

Common Mistakes:

• Thinking markers speed up tests
• Confusing markers with test data
• Assuming markers generate reports

2. Which of the following is the correct way to register a marker named slow in pytest.ini?

easy

A. [markers]
slow: marks tests as slow

B. [pytest]
markers = slow

C. [pytest]
slow = marks tests as slow

D. [markers]
slow = marks tests as slow

Solution

1. Step 1: Identify correct section header

   Markers must be registered under the [markers] section in pytest.ini.

2. Step 2: Check syntax for marker registration

   The correct syntax uses an equals sign = with a description, e.g., slow = marks tests as slow.

3. Final Answer:

   [markers] slow = marks tests as slow -> Option D

4. Quick Check:

   Markers section + equals sign = correct syntax [OK]

Hint: Use [markers] section and '=' to register markers [OK]

Common Mistakes:

• Using [pytest] instead of [markers]
• Using colon ':' instead of '='
• Listing markers without description

3. Given this pytest.ini content:

[markers]
api = marks tests as api tests
slow = marks tests as slow

What happens if you run pytest -m slow?

medium

A. Only tests marked with @pytest.mark.slow will run

B. All tests will run except those marked slow

C. Tests marked with @pytest.mark.api will run

D. Pytest will show a warning about unknown marker

Solution

1. Step 1: Understand marker filtering with -m option

   The -m option runs tests matching the given marker name.

2. Step 2: Match marker name with registered markers

   Since slow is registered and used, pytest -m slow runs only tests marked with @pytest.mark.slow.

3. Final Answer:

   Only tests marked with @pytest.mark.slow will run -> Option A

4. Quick Check:

   pytest -m marker = runs tests with that marker [OK]

Hint: pytest -m runs tests with the named marker only [OK]

Common Mistakes:

• Thinking -m excludes tests with the marker
• Confusing marker names
• Expecting warnings when marker is registered

4. You added this to your pytest.ini:

[markers]
fast marks tests as fast

But when running tests, pytest shows a warning about unknown marker 'fast'. What is the problem?

medium

A. Marker name 'fast' is reserved and cannot be used

B. Markers section header is misspelled

C. Missing '=' sign between marker name and description

D. pytest.ini file is in the wrong directory

Solution

1. Step 1: Check marker registration syntax

   The marker line must have an equals sign = between the marker name and its description.

2. Step 2: Identify missing '=' causing warning

   Here, fast marks tests as fast lacks '=', so pytest treats 'fast' as unknown marker.

3. Final Answer:

   Missing '=' sign between marker name and description -> Option C

4. Quick Check:

   Marker line needs '=' sign [OK]

Hint: Always use '=' between marker and description [OK]

Common Mistakes:

• Forgetting '=' sign
• Misspelling [markers] header
• Placing pytest.ini in wrong folder

5. You want to register two markers in pytest.ini: db for database tests and ui for user interface tests. Which pytest.ini content correctly registers both markers?

hard

A. [markers]
db = marks tests as database tests
ui = marks tests as user interface tests

B. [pytest]
markers = db, ui

C. [markers]
db: marks database tests
ui: marks UI tests

D. [pytest]
db = database tests
ui = UI tests

Solution

1. Step 1: Confirm correct section header

   Markers must be under the [markers] section, not [pytest].

2. Step 2: Verify correct syntax for each marker

   Each marker line uses = with a description, e.g., db = marks tests as database tests.

3. Step 3: Check all markers are listed separately

   Both db and ui markers are listed on separate lines with descriptions.

4. Final Answer:

   [markers] db = marks tests as database tests ui = marks tests as user interface tests -> Option A

5. Quick Check:

   Separate lines under [markers] with '=' for each marker [OK]

Hint: List each marker under [markers] with '=' and description [OK]

Common Mistakes:

• Using [pytest] instead of [markers]
• Using commas to list markers
• Using ':' instead of '='