@Test annotation in JUnit - Test Execution Trace

Test Overview

This test uses the @Test annotation to mark a method as a test case. It verifies that the addition of two numbers returns the correct result.

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 a = 5;
        int b = 3;
        int result = a + b;
        assertEquals(8, result, "5 + 3 should equal 8");
    }
}

Execution Trace - 5 Steps

Step	Action	System State	Assertion	Result
1	JUnit test runner starts and scans for methods annotated with @Test	Test class CalculatorTest loaded with method testAddition marked as @Test	-	PASS
2	JUnit invokes the testAddition() method	Inside testAddition method, variables a=5 and b=3 initialized	-	PASS
3	Calculate result = a + b	result variable holds value 8	-	PASS
4	Assert that result equals 8 using assertEquals	Comparing expected value 8 with actual result 8	assertEquals(8, result) verifies values are equal	PASS
5	JUnit marks testAddition as PASSED and finishes test run	Test report shows testAddition PASSED	-	PASS

Failure Scenario

Failing Condition: If the addition result is not equal to 8

Execution Trace Quiz - 3 Questions

What does the @Test annotation do in this code?

A Marks the method as a test case to be run by JUnit

B Declares a variable

C Imports the JUnit library

D Runs the main application

Key Result

Using the @Test annotation clearly marks test methods, allowing the test runner to find and execute them automatically. This keeps tests organized and easy to run.