First JUnit test - Test Execution Trace

Test Overview

This test checks if the addition of two numbers works correctly using JUnit. It verifies that 2 + 3 equals 5.

Test Code - JUnit 5

JUnit

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

public class CalculatorTest {

    @Test
    public void testAddition() {
        int result = 2 + 3;
        assertEquals(5, result, "2 + 3 should equal 5");
    }
}

Execution Trace - 4 Steps

Step	Action	System State	Assertion	Result
1	Test starts	JUnit test runner initializes the CalculatorTest class	-	PASS
2	Runs testAddition method	Inside testAddition method, calculation 2 + 3 is performed	-	PASS
3	Calls assertEquals to check if result equals 5	assertEquals compares expected value 5 with actual result 5	assertEquals(5, result) verifies 5 == 5	PASS
4	Test completes successfully	Test runner marks testAddition as passed	-	PASS

Failure Scenario

Failing Condition: If the addition result is not 5, for example if result is 4

Execution Trace Quiz - 3 Questions

What does the assertEquals method check in this test?

A If the actual result equals the expected value 5

B If the test method runs without errors

C If the CalculatorTest class compiles

D If the test runner starts correctly

Key Result

Always include clear assertions in your tests to verify expected outcomes. This helps catch errors early and ensures your code works as intended.