Checking exception message in JUnit - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to check that the exception is thrown.

JUnit

assertThrows(IllegalArgumentException.class, () -> methodThatThrows([1]));

Drag options to blanks, or click blank then click option'

A5

B""

Cnull

Dnew Object()

Attempts:

3 left

💡 Hint

Common Mistakes

Passing a non-null value that does not cause exception.

Using incorrect syntax for lambda expression.

The method expects a null input to throw IllegalArgumentException.

2fill in blank

medium

Complete the code to capture the exception and check its message.

JUnit

Exception exception = assertThrows(IllegalArgumentException.class, () -> methodThatThrows(null));
assertEquals([1], exception.getMessage());

Drag options to blanks, or click blank then click option'

A"Invalid input"

B"Exception occurred"

C"Error"

D"Null value"

Attempts:

3 left

💡 Hint

Common Mistakes

Using assertTrue instead of assertEquals for message check.

Checking wrong exception message string.

The exception message expected is "Invalid input".

3fill in blank

hard

Fix the error in the assertion to correctly check the exception message.

JUnit

assertEquals([1], exception.getMessage());

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A"Error"

Bexception.getMessage()

Cnull

D"Invalid input"

Attempts:

3 left

💡 Hint

Common Mistakes

Swapping expected and actual arguments in assertEquals.

Using null as expected message.

The expected message should be the first argument in assertEquals.

4fill in blank

hard

Fill both blanks to check exception type and message in one test.

JUnit

Throwable thrown = assertThrows([1].class, () -> methodThatThrows(null));
assertTrue(thrown.getMessage().contains([2]));

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AIllegalArgumentException

B"Invalid"

C"Error"

DNullPointerException

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong exception class.

Checking message with exact match instead of contains.

The test checks that IllegalArgumentException is thrown and its message contains "Invalid".

5fill in blank

hard

Fill all three blanks to assert exception type, message, and cause.

JUnit

IllegalArgumentException ex = assertThrows([1].class, () -> methodThatThrows(null));
assertEquals([2], ex.getMessage());
assertNotNull(ex.getCause());
assertTrue(ex.getCause() instanceof [3]);

Drag options to blanks, or click blank then click option'

AIllegalArgumentException

B"Invalid input"

CNullPointerException

DRuntimeException

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong exception class or cause type.

Checking message with contains instead of equals.

The test asserts the exception type, exact message, and that the cause is a NullPointerException.