Line and branch coverage in JUnit - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create a JUnit test method that checks if the sum method returns the correct result.

JUnit

import static org.junit.jupiter.api.Assertions.assertEquals;
import org.junit.jupiter.api.Test;

public class CalculatorTest {
    @Test
    public void testSum() {
        Calculator calc = new Calculator();
        int result = calc.sum(2, 3);
        assertEquals([1], result);
    }
}

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

A5

B7

C4

D6

Attempts:

3 left

💡 Hint

Common Mistakes

Using the wrong expected value in assertEquals.

Forgetting to import assertEquals.

The sum of 2 and 3 is 5, so the assertion should check for 5.

2fill in blank

medium

Complete the code to add a test method that checks if the isPositive method returns true for positive numbers.

JUnit

import static org.junit.jupiter.api.Assertions.assertTrue;
import org.junit.jupiter.api.Test;

public class NumberTest {
    @Test
    public void testIsPositive() {
        NumberChecker checker = new NumberChecker();
        assertTrue(checker.isPositive([1]));
    }
}

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

A-5

B5

C-1

D0

Attempts:

3 left

💡 Hint

Common Mistakes

Testing with zero or negative numbers expecting true.

Not importing assertTrue.

The method isPositive should return true for positive numbers, so 5 is correct.

3fill in blank

hard

Fix the error in the test method to correctly check if the max method returns the larger number.

JUnit

import static org.junit.jupiter.api.Assertions.assertEquals;
import org.junit.jupiter.api.Test;

public class MaxTest {
    @Test
    public void testMax() {
        MaxFinder finder = new MaxFinder();
        int max = finder.max(10, 20);
        assertEquals([1], max);
    }
}

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

A30

B10

C0

D20

Attempts:

3 left

💡 Hint

Common Mistakes

Using the smaller number as expected value.

Confusing the order of parameters.

The max method should return the larger number, which is 20 in this case.

4fill in blank

hard

Fill both blanks to complete the test method that checks if the isEven method returns true for even numbers and false for odd numbers.

JUnit

import static org.junit.jupiter.api.Assertions.assert[1];
import static org.junit.jupiter.api.Assertions.assertFalse;
import org.junit.jupiter.api.Test;

public class EvenOddTest {
    @Test
    public void testIsEven() {
        EvenOddChecker checker = new EvenOddChecker();
        assert[2](checker.isEven(4));
        assertFalse(checker.isEven(5));
    }
}

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

ATrue

BFalse

CEquals

DNull

Attempts:

3 left

💡 Hint

Common Mistakes

Using assertFalse instead of assertTrue for even number test.

Using assertEquals incorrectly here.

assertTrue is used to check if the method returns true for even numbers.

5fill in blank

hard

Fill all three blanks to complete the test method that verifies the behavior of the divide method, including handling division by zero.

JUnit

import static org.junit.jupiter.api.Assertions.assert[1];
import static org.junit.jupiter.api.Assertions.assertThrows;
import org.junit.jupiter.api.Test;

public class DivisionTest {
    @Test
    public void testDivide() {
        Calculator calc = new Calculator();
        assert[2](2, calc.divide(10, 5));
        assertThrows([3].class, () -> calc.divide(10, 0));
    }
}

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

AEquals

BassertEquals

CArithmeticException

DIllegalArgumentException

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong assertion method names.

Expecting wrong exception type for division by zero.

assertEquals checks the division result, and assertThrows expects an ArithmeticException for division by zero.