Why patterns improve test quality in JUnit - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create a test method using JUnit 5.

JUnit

@Test
void [1]() {
    assertEquals(4, 2 + 2);
}

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

AadditionTest

BsumTest

CtestAddition

DcheckSum

Attempts:

3 left

💡 Hint

Common Mistakes

Using vague method names like 'test1' or 'check'.

Not using the @Test annotation.

The method name additionTest clearly describes the test purpose, improving readability and test quality.

2fill in blank

medium

Complete the code to use the Arrange-Act-Assert pattern in the test.

JUnit

@Test
void testMultiply() {
    // Arrange
    int a = 3;
    int b = 5;

    // Act
    int result = a [1] b;

    // Assert
    assertEquals(15, result);
}

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

A*

B+

C-

D/

Attempts:

3 left

💡 Hint

Common Mistakes

Using addition or subtraction instead of multiplication.

Skipping the Arrange-Act-Assert structure.

The Act step performs multiplication using the * operator, matching the expected result.

3fill in blank

hard

Fix the error in the test assertion to correctly check for null.

JUnit

@Test
void testObjectIsNull() {
    Object obj = null;
    assert[1](obj);
}

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

ATrue

BEquals

CNotNull

DNull

Attempts:

3 left

💡 Hint

Common Mistakes

Using assertNotNull when the object is null.

Using assertEquals instead of assertNull.

The assertNull method correctly asserts that obj is null, improving test accuracy.

4fill in blank

hard

Fill both blanks to use the Given-When-Then pattern in comments.

JUnit

@Test
void testDivide() {
    // [1]
    int numerator = 10;
    int denominator = 2;

    // [2]
    int result = numerator / denominator;

    assertEquals(5, result);
}

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

AGiven

BArrange

CWhen

DAct

Attempts:

3 left

💡 Hint

Common Mistakes

Mixing up Arrange/Act with Given/When.

Not using clear comments to separate test steps.

The Given comment describes the setup, and When describes the action, following the Given-When-Then pattern.

5fill in blank

hard

Fill all three blanks to create a parameterized test using JUnit 5.

JUnit

@ParameterizedTest
@ValueSource(ints = {2, 4, 6})
void testIsEven([1] number) {
    // [2]
    boolean isEven = number % 2 [3] 0;
    assertTrue(isEven);
}

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

Aint

BArrange

C==

Dboolean

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong parameter types.

Omitting comments that clarify test steps.

Using assignment '=' instead of equality '==' in condition.

The parameter int is used for numbers, the comment Arrange marks setup, and == checks equality, making the test clear and reusable.