pytest.ini configuration - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

Output of pytest with custom markers in pytest.ini

Given the following pytest.ini configuration and test code, what will be the output when running pytest with the marker filter -m slow?

PyTest

[pytest]
markers =
    slow: marks tests as slow

# test_sample.py
import pytest

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

def test_fast():
    assert True

A Only <code>test_slow</code> runs and passes; <code>test_fast</code> is skipped.

B Both <code>test_slow</code> and <code>test_fast</code> run and pass.

C Only <code>test_fast</code> runs and passes; <code>test_slow</code> is skipped.

D No tests run because marker <code>slow</code> is not recognized.

💡 Hint

The -m option runs tests matching the given marker.

The pytest.ini declares the marker slow. Running pytest with -m slow runs only tests marked with @pytest.mark.slow. So test_slow runs and passes; test_fast is skipped.

❓ assertion

intermediate

Assertion behavior with pytest.ini addopts

If pytest.ini contains addopts = --maxfail=1 --tb=short, what will happen when two tests fail in a test suite?

A Pytest stops after the first failure but shows full tracebacks.

B Pytest runs all tests and shows full tracebacks for failures.

C Pytest runs all tests and shows short tracebacks.

D Pytest stops after the first failure and shows a short traceback.

💡 Hint

The --maxfail option limits failures before stopping.

The --maxfail=1 option stops pytest after the first failure. The --tb=short option shows shorter tracebacks. So pytest stops after one failure and shows a short traceback.

❓ locator

advanced

Correct pytest.ini section for configuring test paths

Which section header is correct in pytest.ini to specify the directory where pytest should look for tests using testpaths?

A

[pytest]
testpaths = tests

B

[pytest.ini]
testpaths = tests

C

[config]
testpaths = tests

D

[tool:pytest]
testpaths = tests

💡 Hint

The official pytest configuration section is [pytest].

The correct section header in pytest.ini is [pytest]. Other headers like [tool:pytest] are used in other config files but not pytest.ini.

🔧 Debug

advanced

Identify the error in pytest.ini configuration

Given this pytest.ini content, what error will pytest raise when running?

PyTest

[pytest]
markers =
    slow: marks tests as slow
    fast marks tests as fast

A pytest ignores the invalid marker and runs all tests normally.

B pytest raises a ConfigError due to missing colon in marker declaration.

C pytest raises a SyntaxError parsing pytest.ini.

D pytest runs but warns about unknown marker 'fast'.

💡 Hint

Check the marker syntax carefully.

The second marker line misses a colon after 'fast'. This causes pytest to raise a ConfigError about invalid marker syntax.

❓ framework

expert

Effect of pytest.ini on test discovery and execution

Consider this pytest.ini: [pytest] testpaths = tests python_files = check_*.py addopts = -v --disable-warnings What is the combined effect of these settings when running pytest without arguments?

A Pytest looks only in the 'tests' folder for all test files, runs tests quietly, and suppresses warnings.

B Pytest looks in all folders for files starting with 'check_' and ending with '.py', runs tests verbosely, and shows warnings.

C Pytest looks only in the 'tests' folder for files starting with 'check_' and ending with '.py', runs tests verbosely, and suppresses warnings.

D Pytest looks in all folders for all test files, runs tests quietly, and shows warnings.

💡 Hint

Check each pytest.ini option's effect on discovery and output.

The 'testpaths = tests' limits discovery to the 'tests' directory. 'python_files = check_*.py' limits test files to those matching that pattern. 'addopts = -v --disable-warnings' runs tests verbosely and disables warnings.

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