assertDoesNotThrow in JUnit - Test Execution Trace

Test Overview

This test verifies that a specific piece of code runs without throwing any exceptions. It uses assertDoesNotThrow to ensure the code block executes safely.

Test Code - JUnit 5

JUnit

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

public class NoExceptionTest {

    @Test
    void testNoExceptionThrown() {
        assertDoesNotThrow(() -> {
            // Code that should not throw an exception
            int result = 10 / 2;
            System.out.println("Result is: " + result);
        });
    }
}

Execution Trace - 4 Steps

Step	Action	System State	Assertion	Result
1	Test starts	JUnit test runner initialized	-	PASS
2	Runs lambda code inside assertDoesNotThrow	Code executes: int result = 10 / 2; prints 'Result is: 5'	No exception is thrown during execution	PASS
3	assertDoesNotThrow verifies no exception occurred	Test method completes successfully	assertDoesNotThrow passes as no exception was thrown	PASS
4	Test ends	JUnit reports test passed	-	PASS

Failure Scenario

Failing Condition: The code inside assertDoesNotThrow throws an exception

Execution Trace Quiz - 3 Questions

What does assertDoesNotThrow check in this test?

A That an exception is thrown by the code block

B That no exception is thrown by the code block

C That the code block returns a specific value

D That the code block runs slower than a timeout

Key Result

Use assertDoesNotThrow to clearly verify that a code block runs without exceptions, improving test clarity and intent.