pytest-timeout for time limits - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

What happens when a test exceeds the timeout?

Consider this pytest test using pytest-timeout to limit execution time to 1 second.

import time
import pytest

@pytest.mark.timeout(1)
def test_sleep():
    time.sleep(2)

What is the test result when you run this?

PyTest

import time
import pytest

@pytest.mark.timeout(1)
def test_sleep():
    time.sleep(2)

A The test fails due to timeout after 1 second.

B The test passes because sleep is allowed to finish.

C The test raises a SyntaxError because of incorrect decorator usage.

D The test is skipped automatically by pytest.

💡 Hint

Think about what pytest-timeout does when a test runs longer than allowed.

The @pytest.mark.timeout(1) decorator stops the test if it runs longer than 1 second. Since time.sleep(2) sleeps for 2 seconds, the test fails due to timeout.

❓ assertion

intermediate

Which assertion correctly checks timeout exception?

You want to test that a function long_task() times out after 1 second using pytest-timeout. Which assertion correctly verifies the timeout?

PyTest

import pytest

@pytest.mark.timeout(1)
def test_long_task():
    long_task()

A

with pytest.raises(pytest.TimeoutException):
    long_task()

B assert long_task() == 'timeout'

C assert long_task() is None

D

with pytest.raises(TimeoutError):
    long_task()

💡 Hint

Check which exception pytest-timeout raises on timeout.

pytest-timeout raises TimeoutError when a test times out. So the correct way to assert timeout is using pytest.raises(TimeoutError).

🔧 Debug

advanced

Why does the timeout not stop the test?

This test uses pytest-timeout but the test runs longer than the timeout without stopping:

import time
import pytest

@pytest.mark.timeout(1)
def test_wait():
    time.sleep(3)

What is the most likely reason the timeout is ignored?

A The test is run with <code>pytest --timeout=0</code> which disables timeout.

B The <code>@pytest.mark.timeout</code> decorator is misspelled.

C The <code>pytest-timeout</code> plugin is not installed or not active.

D The test function name does not start with 'test_'.

💡 Hint

Check if the plugin is installed and enabled.

If pytest-timeout is not installed or not enabled, the @pytest.mark.timeout decorator has no effect and tests run without timeout.

❓ framework

advanced

How to set a global timeout for all tests?

You want to apply a 2-second timeout to all tests in your pytest suite without adding decorators to each test. Which is the best way?

A Add <code>--timeout=2</code> option in pytest command line or pytest.ini config.

B Set <code>timeout=2</code> inside each test function body.

C Add <code>@pytest.mark.timeout(2)</code> to each test function manually.

D Use <code>pytest.set_timeout(2)</code> in conftest.py.

💡 Hint

Think about pytest configuration options.

You can set a global timeout by passing --timeout=2 on the command line or adding timeout = 2 under the [pytest] section in pytest.ini. This applies timeout to all tests automatically.

🧠 Conceptual

expert

What is the effect of timeout_method=thread in pytest-timeout?

pytest-timeout supports different timeout methods. What happens when you set timeout_method=thread?

A The test process is forcibly killed immediately on timeout.

B The test is stopped by raising an exception in a separate thread without killing the process.

C Timeout is ignored and tests run without limits.

D The test is paused and resumed after timeout.

💡 Hint

Consider how threads can interrupt test execution.

With timeout_method=thread, pytest-timeout uses a separate thread to raise a timeout exception inside the test thread. This stops the test by exception without killing the whole process.