Single assertion per test debate in JUnit - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to assert that the sum of 2 and 3 equals 5.

JUnit

assertEquals([1], 2 + 3);

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A4

B6

C5

D7

Attempts:

3 left

💡 Hint

Common Mistakes

Using the wrong expected value in the assertion.

The assertion checks if 2 + 3 equals 5, which is true.

2fill in blank

medium

Complete the code to assert that a string is not null.

JUnit

assertNotNull([1]);

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AsomeString

B""

C"hello"

Dnull

Attempts:

3 left

💡 Hint

Common Mistakes

Passing a literal null or string literal instead of a variable.

The assertion checks that the variable someString is not null.

3fill in blank

hard

Fix the error in the assertion that checks if two objects are equal.

JUnit

assertEquals([1], expectedObject, actualObject);

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A"message"

BexpectedObject

CactualObject

Dnull

Attempts:

3 left

💡 Hint

Common Mistakes

Swapping expected and actual arguments.

Passing objects in wrong order.

The first argument is an optional message string. The correct order is assertEquals(message, expected, actual).

4fill in blank

hard

Fill both blanks to create a test that asserts a list contains exactly 3 elements and is not empty.

JUnit

assertEquals([1], myList.size());
assertFalse([2]);

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A3

BmyList.isEmpty()

CmyList.size() == 3

DmyList.isEmpty() == false

Attempts:

3 left

💡 Hint

Common Mistakes

Using incorrect expressions inside assertions.

Confusing assertFalse with assertTrue.

The first assertion checks the list size is 3. The second asserts the list is not empty by checking myList.isEmpty() is false.

5fill in blank

hard

Fill all three blanks to write a test that asserts a string is not null, contains 'test', and has length 4.

JUnit

assertNotNull([1]);
assertTrue([2]);
assertEquals([3], [1].length());

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

AinputString

BinputString.contains("test")

C4

DinputString.length()

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong variable names or literals.

Mixing up length checks and contains checks.

The test checks that inputString is not null, contains the substring 'test', and its length is 4.