JUnit comparison of 4 and 5

Russell Bateman
April 2019
last update:

Links

• Migrating from JUnit 4 to JUnit 5
• JUnit4, JUnit5, and Spock: A Comparison
• JUnit 5 vs JUnit 4
• Unit Testing with JUnit - Tutorial

JUnit 4

• Language support never advanced beyond Java 7. I assume this really only means the internal implementation.
• Entire framework contained in single JAR and must become part of the whole even if parts unnecessary.
• Test runner is singly threaded.

JUnit 5

• Supports use of JUnit 4 test suites, test cases, etc. by means of

    <dependency>
      <groupId>org.junit.vintage</groupId>
      <artifactId>junit-vintage-engine</artifactId>
      <version>${junit5.vintage.version}</version>
      <scope>test</scope>
    </dependency>
  
  

• Test runner is multithreaded.
• Composed of three subprojects in different JARs:
  • platform
  • jupiter

    <dependency>
      <groupId>org.junit.jupiter</groupId>
      <artifactId>junit-jupiter-api</artifactId>
        <version>${junit5.jupiter.version}</version>
      <scope>test</scope>
    </dependency>
    
    

  • vintage
• Numerous additions/replacements in terms of annotations.

  JUnit 4	JUnit 5
  @Test	@Test
  @Before	@BeforeEach
  @After	@AfterEach
  @BeforeClass	@BeforeAll
  @AfterClass	@AfterAll
  @Ignore	@Disabled
  @Category	@Tag

• Impose order of test cases (beginning in JUnit 5.4):

  @TestMethodOrder( OrderAnnotation.class )
  public class MyJUnitTest
  {
    @Test
    @Order( 1 )
    public void testSomeCase()
    {
      ...
    }
  
    @Test
    @Order( 2 )
    public void testAnotherCase()
    {
      ...
    }
  
    @Test
    @Order( 3 )
    public void testStillAnotherCase()
    {
      ...
    }
  }
  

• Introduces parameterized test cases. For instance, this test below is set up such that, without duplicating the code, it will run separately for the strings, "Hello" and "World":

  @ParameterizedTest
  @ValueSource( strings = { "Hello", "World" } )
  void testWithStringParameter( String argument )
  {
    System.out.println( "Called with \" + argument + "\"!" );
    assertNotNull( argument );
  }
  
  

  Launched from console, the test will produce (something like) this output:

  testWithStringParameter(String) ✓
  ├─ [1] Hello ✓
  └─ [2] World ✓