@Order for execution order in JUnit - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

Test execution order with @Order annotation

Given the following JUnit 5 test class, what is the order of test method execution?

JUnit

import org.junit.jupiter.api.*;
import org.junit.jupiter.api.MethodOrderer.OrderAnnotation;

@TestMethodOrder(OrderAnnotation.class)
public class SampleTest {

    @Test
    @Order(2)
    void testSecond() {
        System.out.println("Second");
    }

    @Test
    @Order(1)
    void testFirst() {
        System.out.println("First");
    }

    @Test
    @Order(3)
    void testThird() {
        System.out.println("Third");
    }
}

A First, Second, Third

B Second, First, Third

C Third, Second, First

D Execution order is random

💡 Hint

Look at the @Order values and the @TestMethodOrder annotation.

JUnit 5 executes test methods in the order specified by the @Order annotation when @TestMethodOrder(OrderAnnotation.class) is used. Lower order values run first.

❓ assertion

intermediate

Assertion to verify test execution order

Which assertion correctly verifies that a list of executed test names matches the expected order when using @Order annotation?

JUnit

List<String> executedTests = List.of("testFirst", "testSecond", "testThird");
List<String> expectedOrder = List.of("testFirst", "testSecond", "testThird");

A assertArrayEquals(expectedOrder.toArray(), executedTests.toArray());

B assertEquals(expectedOrder, executedTests);

C assertTrue(executedTests.containsAll(expectedOrder));

D assertNotNull(executedTests);

💡 Hint

Check which assertion verifies both order and content equality.

assertArrayEquals compares arrays element by element and order matters. assertEquals on lists also works but assertArrayEquals is more explicit for order verification.

🔧 Debug

advanced

Why is @Order ignored in this test class?

Consider this JUnit 5 test class: import org.junit.jupiter.api.*; public class TestClass { @Test @Order(1) void testA() {} @Test @Order(2) void testB() {} } Why are the tests not executed in the order testA then testB?

A Because @Order values must be unique

B Because @Order annotation is only for JUnit 4

C Because test methods must be static to use @Order

D Because @TestMethodOrder(OrderAnnotation.class) is missing on the class

💡 Hint

Check if the class has the annotation that enables ordering by @Order.

JUnit 5 requires @TestMethodOrder(OrderAnnotation.class) on the test class to enable ordering by @Order annotations. Without it, the order is not guaranteed.

🧠 Conceptual

advanced

Effect of duplicate @Order values

What happens if two test methods in a JUnit 5 test class have the same @Order value when using @TestMethodOrder(OrderAnnotation.class)?

A JUnit runs tests alphabetically ignoring @Order

B JUnit throws a runtime exception and stops execution

C Tests with the same order value run in an undefined order relative to each other

D Tests with duplicate order values are skipped

💡 Hint

Think about how ordering works when priorities are equal.

When multiple tests have the same @Order value, their relative order is not guaranteed and may be arbitrary.

❓ framework

expert

Combining @Order with other TestMethodOrderers

Given a JUnit 5 test class annotated with @TestMethodOrder(MethodOrderer.OrderAnnotation.class), what happens if a test method is missing the @Order annotation?

A The test method is executed before all methods with @Order annotations

B JUnit throws an exception and fails the test run

C The test method is executed after all methods with @Order annotations

D The test method is ignored and not executed

💡 Hint

The default @Order value is 0, and lower values run first.

JUnit assigns a default order value of 0 to test methods without @Order annotation. Since lower order values are executed first, they run before test methods with explicitly assigned higher order values.