Timeout annotations in JUnit - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the purpose of timeout annotations in JUnit?

Timeout annotations in JUnit are used to specify the maximum time a test method should run. If the test exceeds this time, it fails automatically to prevent hanging or long-running tests.

beginner

How do you apply a timeout to a single test method in JUnit 5?

You use the @Timeout annotation above the test method and specify the duration, for example: <br>@Timeout(5) means the test must finish within 5 seconds.

beginner

What happens if a test annotated with @Timeout exceeds the specified time?

The test fails immediately with a timeout exception, indicating it took longer than allowed.

intermediate

Can you apply @Timeout at the class level in JUnit? What does it do?

Yes, applying @Timeout at the class level sets the timeout for all test methods in that class. Each test must complete within the specified time individually.

intermediate

How do you specify timeout duration units in JUnit 5's @Timeout annotation?

You can specify the time unit using the 'unit' parameter, for example: <br>@Timeout(value = 500, unit = java.util.concurrent.TimeUnit.MILLISECONDS) sets a 500 milliseconds timeout.

What is the default time unit for the @Timeout annotation in JUnit 5 if not specified?

A Seconds

B Milliseconds

C Minutes

D Hours

If you do not specify the unit in @Timeout, it defaults to seconds.

Where can you apply the @Timeout annotation in JUnit 5?

A Only on test methods

B On both test methods and test classes

C Only on test classes

D Only on setup methods

@Timeout can be applied on both test methods and test classes to set time limits.

What happens if a test exceeds the timeout specified by @Timeout?

A Test fails with a timeout exception

B Test is skipped

C Test continues running

D Test is retried automatically

JUnit fails the test immediately with a timeout exception if it runs longer than allowed.

Which import is required to use @Timeout in JUnit 5?

A org.junit.jupiter.api.TestTimeout

B org.junit.Timeout

C org.junit.jupiter.api.Timeout

D org.junit.jupiter.api.TimeLimit

The correct import for @Timeout in JUnit 5 is org.junit.jupiter.api.Timeout.

How do you specify a timeout of 2 minutes using @Timeout?

A @Timeout(2)

B @Timeout(value = 2, unit = java.util.concurrent.TimeUnit.SECONDS)

C @Timeout(120)

D @Timeout(value = 2, unit = java.util.concurrent.TimeUnit.MINUTES)

You specify the value and unit explicitly: @Timeout(value = 2, unit = TimeUnit.MINUTES).

Explain how timeout annotations help improve test reliability in JUnit.

Think about what happens when a test runs forever or too slow.

Describe how to use the @Timeout annotation to set a 10-second timeout on a test method.

Remember the default time unit if not specified.