pytest.ini configuration - Test Execution Trace

Test Overview

This test checks that pytest reads the pytest.ini configuration file correctly and applies the specified markers and options during test execution.

Test Code - PyTest

PyTest

import pytest

@pytest.mark.slow
def test_example():
    assert 1 + 1 == 2

# Run with: pytest -m slow

Execution Trace - 4 Steps

Step	Action	System State	Assertion	Result
1	Pytest starts and reads pytest.ini configuration file	pytest.ini file is present with markers and options defined	pytest recognizes the 'slow' marker from pytest.ini	PASS
2	Pytest collects tests and finds test_example marked with @pytest.mark.slow	Test suite includes test_example with 'slow' marker	Test is correctly marked as 'slow'	PASS
3	Pytest runs test_example with marker filter '-m slow'	Only tests marked 'slow' are executed	test_example runs and assertion 1 + 1 == 2 passes	PASS
4	Pytest finishes test run and generates report	Report shows test_example passed with marker 'slow'	Test report includes marker info and test passed status	PASS

Failure Scenario

Failing Condition: pytest.ini file missing or marker 'slow' not defined in pytest.ini

Execution Trace Quiz - 3 Questions

What does pytest.ini configure in this test?

A Changes Python version for tests

B Runs tests in parallel automatically

C Defines the 'slow' marker so pytest recognizes it

D Disables all tests except test_example

Key Result

Always register custom markers in pytest.ini to avoid warnings and ensure pytest recognizes them during test runs.

Practice

1. What is the primary purpose of the pytest.ini file in a pytest project?

easy

A. To install pytest dependencies automatically

B. To store configuration settings for pytest test runs

C. To write test functions and test cases

D. To generate test reports after running tests

Solution

1. Step 1: Understand pytest.ini role

   The pytest.ini file is used to configure pytest behavior before running tests.

2. Step 2: Differentiate from other files

   Test functions are written in Python files, not in pytest.ini. Dependency installation and report generation are handled elsewhere.

3. Final Answer:

   To store configuration settings for pytest test runs -> Option B

4. Quick Check:

   pytest.ini = config file [OK]

Hint: pytest.ini holds settings, not test code or reports [OK]

Common Mistakes:

• Confusing pytest.ini with test script files
• Thinking pytest.ini installs packages
• Assuming pytest.ini generates reports

2. Which of the following is the correct way to set the verbosity level to 2 in pytest.ini?

easy

A. [pytest]
addopts = -vv

B. [pytest]
verbosity = 2

C. [pytest]
verbosity: 2

D. [pytest]
addopts = --verbosity=2

Solution

1. Step 1: Recall pytest verbosity setting

   pytest uses addopts to pass command-line options like -vv for verbosity level 2.

2. Step 2: Check syntax correctness

   [pytest] addopts = -vv correctly uses addopts = -vv. [pytest] verbosity = 2 uses an invalid key verbosity. [pytest] verbosity: 2 uses wrong syntax with colon. [pytest] addopts = --verbosity=2 uses an invalid flag.

3. Final Answer:

   [pytest] addopts = -vv -> Option A

4. Quick Check:

   Verbosity level 2 via addopts = -vv [OK]

Hint: Use addopts with -vv for verbosity level 2 in pytest.ini [OK]

Common Mistakes:

• Using 'verbosity' instead of 'addopts'
• Incorrect syntax with colon instead of equals
• Using unsupported flags like --verbosity

3. Given this pytest.ini content:

[pytest]
markers = slow: marks tests as slow
          smoke: marks smoke tests
addopts = -rs

What will be the effect of running pytest with this configuration?

medium

A. Tests marked as slow or smoke will be skipped automatically

B. pytest will run tests with no output

C. Only tests marked as slow will run

D. pytest will show extra summary info for skipped and failed tests

Solution

1. Step 1: Understand markers and addopts

   The markers section defines labels for tests but does not skip them automatically. The addopts = -rs option tells pytest to show extra summary info for skipped and failed tests.

2. Step 2: Analyze each option

   Tests marked as slow or smoke will be skipped automatically is wrong because markers alone don't skip tests. Only tests marked as slow will run is wrong because no selection is made. pytest will run tests with no output is wrong because -rs increases output detail.

3. Final Answer:

   pytest will show extra summary info for skipped and failed tests -> Option D

4. Quick Check:

   addopts = -rs shows skip/fail summary [OK]

Hint: addopts = -rs shows skip and fail summaries [OK]

Common Mistakes:

• Thinking markers skip tests automatically
• Confusing addopts flags with test selection
• Assuming no output with -rs option

4. You added this to your pytest.ini file:

[pytest]
markers = regression
addopts = --maxfail=3

But when you run pytest, you get an error: ERROR: unknown option: --maxfail=3
What is the most likely cause?

medium

A. The addopts line should use -maxfail=3 instead

B. The pytest.ini file is missing the [pytest] header

C. The pytest version is outdated and does not support --maxfail

D. Markers must be defined after addopts in pytest.ini

Solution

1. Step 1: Understand the error message

   The error says unknown option: --maxfail=3, meaning pytest does not recognize this option.

2. Step 2: Check possible causes

   The addopts line should use -maxfail=3 instead is wrong because --maxfail requires two dashes. The pytest.ini file is missing the [pytest] header is wrong because the header is present. Markers must be defined after addopts in pytest.ini is wrong because order does not matter. The most common cause is an outdated pytest version that lacks support for --maxfail.

3. Final Answer:

   The pytest version is outdated and does not support --maxfail -> Option C

4. Quick Check:

   Unknown option usually means outdated pytest [OK]

Hint: Unknown option often means pytest version too old [OK]

Common Mistakes:

• Changing option syntax incorrectly
• Forgetting to include [pytest] header
• Thinking order of keys matters in pytest.ini

5. You want to configure pytest.ini to:
1. Mark tests with slow and critical labels.
2. Run only tests matching the pattern test_*.py.
3. Stop after 2 failures.

Which of the following pytest.ini configurations achieves all three correctly?

hard

A. [pytest]
markers = slow: slow tests
critical: critical tests
python_files = test_*.py
addopts = --maxfail=2

B. [pytest]
markers = slow
critical
python_files = test_*.py
addopts = -x --maxfail=2

C. [pytest]
markers = slow: slow tests
critical: critical tests
python_files = test_*.py
addopts = -x --maxfail=2

D. [pytest]
markers = slow: slow tests
critical: critical tests
python_files = test_*.py
addopts = --maxfail=2 -x

Solution

1. Step 1: Check markers syntax

   Options A, C, and D correctly define markers with descriptions. [pytest] markers = slow critical python_files = test_*.py addopts = -x --maxfail=2 lacks descriptions, which is allowed but less clear.

2. Step 2: Verify test file pattern

   All options set python_files = test_*.py correctly.

3. Step 3: Confirm failure stop and run options

   [pytest] markers = slow: slow tests critical: critical tests python_files = test_*.py addopts = --maxfail=2 uses addopts = --maxfail=2 which stops after 2 failures but does not stop immediately on first failure. Options C and D add -x which stops after first failure, conflicting with requirement to stop after 2 failures. [pytest] markers = slow critical python_files = test_*.py addopts = -x --maxfail=2 lacks descriptions in markers.

4. Final Answer:

   Markers with descriptions, correct python_files, and stop after 2 failures -> Option A

5. Quick Check:

   Use --maxfail=2 without -x to stop after 2 failures [OK]

Hint: Use --maxfail=2 without -x to stop after 2 failures [OK]

Common Mistakes:

• Adding -x stops after 1 failure, not 2
• Omitting marker descriptions
• Misconfiguring python_files pattern