JUnit 4 vs JUnit 5 (Jupiter) differences - Automation Approaches Compared

Verify basic test execution and annotation differences between JUnit 4 and JUnit 5

Preconditions (2)

Step 1: Create a test class using JUnit 4 annotations

Step 2: Write a test method annotated with @Test that asserts 2 + 2 equals 4

Step 3: Run the JUnit 4 test and verify it passes

Step 4: Create a test class using JUnit 5 (Jupiter) annotations

Step 5: Write a test method annotated with @Test that asserts 2 + 2 equals 4

Step 6: Run the JUnit 5 test and verify it passes

Step 7: Observe differences in annotations such as @Before vs @BeforeEach and @After vs @AfterEach

Step 8: Observe that JUnit 5 supports @DisplayName for test methods

✅ Expected Result: Both JUnit 4 and JUnit 5 tests run successfully and pass. Differences in annotations and features like @DisplayName are observed.

Automation Requirements - JUnit 5 (Jupiter)

Assertions Needed:

Assert that 2 + 2 equals 4

Verify that @BeforeEach and @AfterEach methods run before and after each test

Verify that @DisplayName annotation sets the test display name

Best Practices:

Use JUnit 5 Jupiter API consistently

Use @BeforeEach and @AfterEach instead of JUnit 4's @Before and @After

Use descriptive @DisplayName for test methods

Keep test methods small and focused

Use assertions from org.junit.jupiter.api.Assertions

Automated Solution

JUnit

import org.junit.jupiter.api.*;
import static org.junit.jupiter.api.Assertions.*;

@DisplayName("JUnit 5 Basic Test Class")
public class JUnit5BasicTest {

    @BeforeEach
    void setup() {
        System.out.println("Setup before each test");
    }

    @AfterEach
    void teardown() {
        System.out.println("Teardown after each test");
    }

    @Test
    @DisplayName("Test addition: 2 + 2 = 4")
    void testAddition() {
        assertEquals(4, 2 + 2, "2 + 2 should equal 4");
    }
}

This test class uses JUnit 5 (Jupiter) annotations.

@BeforeEach runs before each test method to setup test conditions.

@AfterEach runs after each test method to cleanup.

@Test marks the test method.

@DisplayName provides a readable name for the test class and method.

assertEquals verifies the expected result.

This shows the key differences from JUnit 4, which uses @Before, @After, and lacks @DisplayName.

Common Mistakes - 3 Pitfalls

Using JUnit 4 annotations like @Before and @After in JUnit 5 tests

Not importing org.junit.jupiter.api.Assertions and using JUnit 4 assertions

Not using @DisplayName to improve test readability

Bonus Challenge

Now add parameterized tests in JUnit 5 to test addition with multiple input pairs

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