Test classes and naming in JUnit - Practice Problems & Coding Challenges

Challenge - 5 Problems

🧠 Conceptual

intermediate

Purpose of Test Class Naming Conventions

Why is it important to follow naming conventions for test classes in JUnit?

A To ensure test classes are easily identifiable and grouped logically in reports and IDEs

B To make test classes run faster during execution

C To reduce the size of the compiled test code

D To prevent test classes from being executed accidentally

💡 Hint

Think about how naming helps humans and tools recognize test code.

Proper naming helps developers and tools quickly find and organize tests, improving maintainability and clarity.

❓ Predict Output

intermediate

JUnit Test Class Naming and Execution

Given the following JUnit test classes, which one will be automatically detected and run by default JUnit 5 test runners?

JUnit

public class CalculatorTest {
    @org.junit.jupiter.api.Test
    void testAdd() {}
}

public class CalculatorTests {
    @org.junit.jupiter.api.Test
    void testSubtract() {}
}

public class TestCalculator {
    @org.junit.jupiter.api.Test
    void testMultiply() {}
}

public class CalcTest {
    @org.junit.jupiter.api.Test
    void testDivide() {}
}

A All four classes are detected

B Only CalculatorTest and CalculatorTests are detected

C Only TestCalculator is detected

D Only CalculatorTest is detected

💡 Hint

JUnit 5 detects any class with @Test annotations regardless of name by default.

JUnit 5 does not require specific naming conventions to detect tests; it runs any class with @Test methods.

❓ assertion

advanced

Correct Assertion for Test Class Naming Check

Which assertion correctly verifies that a test class name ends with 'Test' in a JUnit test?

JUnit

String className = "CalculatorTest";

A assertFalse(className.contains("Test"));

B assertEquals(className.startsWith("Test"), true);

C assertEquals(className.length(), 4);

D assertTrue(className.endsWith("Test"));

💡 Hint

Check the method that tests if a string ends with a specific suffix.

assertTrue with endsWith("Test") correctly checks the class name suffix.

🔧 Debug

advanced

Debugging a Test Class Naming Issue

Consider this JUnit 5 test class:

public class calculatorTest {
    @org.junit.jupiter.api.Test
    void testAdd() {}
}

Why might this class cause confusion or issues in a team project?

A Missing @Test annotation on the method

B Class name does not follow Java naming conventions (should start with uppercase letter)

C Test method name does not start with 'test'

D Class is missing a package declaration

💡 Hint

Java class names should follow standard capitalization rules.

Class names should start with uppercase letters to follow Java conventions and avoid confusion.

❓ framework

expert

JUnit 5 Test Class Discovery Rules

Which statement correctly describes how JUnit 5 discovers test classes by default?

A JUnit 5 only runs classes whose names end with 'Test' or 'Tests'

B JUnit 5 requires test classes to extend a specific base test class to be discovered

C JUnit 5 runs any class containing at least one method annotated with @Test, regardless of class name

D JUnit 5 only runs classes located in a 'test' package

💡 Hint

Think about how JUnit 5 improved test discovery compared to older versions.

JUnit 5 uses annotations to find tests, not naming or inheritance conventions.