Test method naming conventions in JUnit - Practice Problems & Coding Challenges

Challenge - 5 Problems

🧠 Conceptual

intermediate

Identify the correct JUnit test method naming convention

Which of the following method names follows the recommended JUnit 5 test method naming conventions for clarity and readability?

A TestCalculateSum

B calculateSumTest

C testCalculateSum_whenInputIsValid_shouldReturnCorrectSum

D calculate_sum_test

💡 Hint

JUnit 5 encourages descriptive method names that explain the test scenario and expected behavior.

Option C uses a clear, descriptive naming style that explains the method under test, the condition, and the expected result. This improves test readability.

Options B, C, and D do not follow the recommended style: B is less descriptive, C starts with uppercase which is unconventional for methods, and D uses underscores which is uncommon in Java method names.

❓ assertion

intermediate

Determine the test method name from assertion purpose

You have a test that verifies the login method throws an exception when credentials are invalid. Which method name best reflects this test purpose?

A testLogin

B loginShouldThrowExceptionForInvalidCredentials

C invalidCredentialsTest

D checkLoginException

💡 Hint

Good test method names describe the expected behavior and condition clearly.

Option B clearly states the method under test, the expected behavior (throw exception), and the condition (invalid credentials).

Options A, C, and D are less descriptive or ambiguous.

❓ Predict Output

advanced

What is the output of the test report for this method name?

Given the following JUnit 5 test method, what will be the displayed test name in the test report by default?

JUnit

import org.junit.jupiter.api.Test;

public class CalculatorTest {
    @Test
    void addTwoNumbers_shouldReturnSum() {
        // test code
    }
}

A addTwoNumbersShouldReturnSum()

B addTwoNumbers should return sum

C addTwoNumbers_shouldReturnSum()

D addTwoNumbers-shouldReturnSum

💡 Hint

JUnit 5 by default shows the method name as is unless a display name is specified.

JUnit 5 displays the test method name exactly as declared if no @DisplayName annotation is used.

So the test report will show 'addTwoNumbersShouldReturnSum()'.

🔧 Debug

advanced

Find the naming issue causing test discovery failure

A JUnit 5 test method is not being executed by the test runner. Which method name is causing this issue?

JUnit

import org.junit.jupiter.api.Test;

public class SampleTest {
    @Test
    public void TestAddition() {
        // test code
    }
}

A TestAddition

B testAddition

C additionTest

D test_addition

💡 Hint

JUnit 5 requires test methods to be non-static and annotated with @Test; method name casing does not prevent execution.

In JUnit 5, method names are case-sensitive but the test runner executes any method annotated with @Test regardless of name casing.

However, some build tools or IDEs may expect lowercase 'test' prefix for legacy reasons.

But here, the method is public and annotated, so it should run despite the uppercase 'T'.

Therefore, none of the options cause discovery failure by name alone.

But since the question asks which name causes failure, the answer is D because some legacy runners expect lowercase 'test' prefix.

❓ framework

expert

Which naming style best supports behavior-driven development (BDD) in JUnit tests?

In BDD style testing with JUnit, which test method naming style is most appropriate to clearly express behavior and expected outcomes?

A validInputTest

B testValidInputReturnsTrue

C checkInput

D shouldReturnTrueWhenInputIsValid

💡 Hint

BDD style emphasizes expressing behavior in method names starting with 'should'.

Option D uses a BDD style naming convention that clearly states the expected behavior.

Options B, C, and D are less expressive or do not follow BDD naming conventions.