assertDoesNotThrow in JUnit - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the purpose of assertDoesNotThrow in JUnit?

assertDoesNotThrow checks that a block of code runs without throwing any exceptions. It helps confirm that the tested code executes smoothly.

beginner

How do you use assertDoesNotThrow in a test method?

You pass a lambda or method reference containing the code to test. For example:<br>assertDoesNotThrow(() -> someMethod());

beginner

What happens if the code inside assertDoesNotThrow throws an exception?

The test fails because assertDoesNotThrow expects no exceptions. The thrown exception causes the assertion to fail.

intermediate

Can assertDoesNotThrow return a value?

Yes, it returns the result of the executed code block if no exception is thrown. This allows further assertions on the returned value.

intermediate

Why is assertDoesNotThrow useful compared to a try-catch block in tests?

It makes tests cleaner and clearer by directly expressing the expectation that no exception should occur, avoiding manual try-catch and fail calls.

What does assertDoesNotThrow verify in a JUnit test?

A That the code does not throw any exception

B That the code throws an exception

C That the code returns null

D That the code runs slower than expected

assertDoesNotThrow checks that no exceptions are thrown during code execution.

How do you pass the code to test inside assertDoesNotThrow?

A As a string

B As a lambda or method reference

C As an integer

D As a boolean

You provide a lambda expression or method reference representing the code block to test.

What happens if the tested code throws an exception inside assertDoesNotThrow?

A The test passes

B The test retries automatically

C The test is skipped

D The test fails

The test fails because assertDoesNotThrow expects no exceptions.

Can assertDoesNotThrow return the result of the tested code?

A Only if the code returns void

B No

C Yes

D Only if the code throws an exception

It returns the result if no exception is thrown, allowing further checks.

Why might assertDoesNotThrow be preferred over try-catch in tests?

A It makes tests clearer and simpler

B It hides exceptions

C It makes tests longer

D It slows down test execution

It simplifies tests by clearly stating the expectation without manual try-catch blocks.

Explain how assertDoesNotThrow works and when you would use it in a test.

Think about testing code that should run smoothly without errors.

Describe the benefits of using assertDoesNotThrow instead of a try-catch block in JUnit tests.

Consider how test readability and simplicity improve.