pyproject.toml configuration in PyTest - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

Output of pytest with custom testpaths in pyproject.toml

Given this pyproject.toml configuration, what will pytest discover and run?

PyTest

[tool.pytest.ini_options]
testpaths = ["tests/integration", "tests/unit"]

A Pytest runs tests in all folders including 'tests/integration' and 'tests/unit'.

B Pytest runs tests in all folders except 'tests/integration' and 'tests/unit'.

C Pytest runs tests only in the root folder, ignoring subfolders.

D Pytest runs tests only in 'tests/integration' and 'tests/unit' folders.

💡 Hint

The testpaths option limits where pytest looks for tests.

The testpaths setting in pyproject.toml tells pytest to only look for tests inside the specified folders. Here, only 'tests/integration' and 'tests/unit' are included.

❓ assertion

intermediate

Correct assertion for pytest capturing output

You want to check that your function prints 'Hello World' when run. Which pytest assertion correctly tests this using capsys?

PyTest

def greet():
    print("Hello World")

def test_greet(capsys):
    greet()
    captured = capsys.readouterr()
    # Which assertion below is correct?

A assert captured.err == "Hello World\n"

B assert captured.out == "Hello World"

C assert captured.out == "Hello World\n"

D assert captured.out.contains("Hello World")

💡 Hint

Remember print adds a newline character at the end.

When using capsys, captured.out contains stdout including newlines. The print function adds a newline, so the output ends with '\n'.

❓ locator

advanced

Identify the correct pytest marker configuration in pyproject.toml

Which pyproject.toml snippet correctly registers a custom marker named 'slow' with a description?

A

[tool.pytest.ini_options]
markers = "slow: marks tests as slow to run"

B

[tool.pytest.ini_options]
markers = ["slow: marks tests as slow to run"]

C

[tool.pytest.ini_options]
markers = {slow = "marks tests as slow to run"}

D

[tool.pytest.ini_options]
markers = slow: marks tests as slow to run

💡 Hint

Markers must be a list of strings with 'name: description' format.

The markers option expects a list of strings, each string describing a marker name and its purpose separated by a colon.

🔧 Debug

advanced

Why does pytest ignore tests in a subfolder despite pyproject.toml settings?

You set testpaths = ["tests"] in pyproject.toml, but pytest does not find tests in tests/api. What is the most likely cause?

A The test files in <code>tests/api</code> do not start with 'test_' or end with '_test.py'.

B The <code>pyproject.toml</code> file is not in the project root directory.

C The <code>tests/api</code> folder lacks an __init__.py file, so pytest skips it.

D Pytest requires explicit inclusion of subfolders in <code>testpaths</code>.

💡 Hint

Pytest discovers tests by file name patterns by default.

Pytest looks for test files matching patterns like 'test_*.py' or '*_test.py'. If files in 'tests/api' do not follow this, pytest ignores them even if the folder is included.

❓ framework

expert

Effect of adding 'addopts' in pyproject.toml on pytest runs

Given this pyproject.toml snippet, what is the effect of the addopts option when running pytest?

PyTest

[tool.pytest.ini_options]
addopts = "-v --maxfail=2"

A Pytest runs in verbose mode and stops after 2 test failures.

B Pytest runs with 2 workers in parallel and verbose output.

C Pytest runs with verbose output and retries failed tests twice.

D Pytest runs with maximum 2 tests executed and verbose output.

💡 Hint

The --maxfail option limits how many failures stop the test run.

The addopts option adds command-line arguments to every pytest run. Here, -v enables verbose output, and --maxfail=2 stops testing after two failures.