JUnit Annotations

JUnit is a framework used for writing and running tests in Java. It provides several annotations to help manage test execution. Here’s an explanation of the most commonly used annotations:

• Test: Marks a method as a test case. This is the most basic and widely used annotation. Methods with this annotation are executed as test cases by JUnit.
• @Before: Indicates that a method should run before each test method. It is useful for setting up any resources or state that tests require.
• @After: Marks a method to run after each test method. It’s typically used to clean up any resources that were set up in the @Before method.
• @BeforeClass: Specifies that a method should run once before any of the test methods in the class. This method is static and is often used to initialize resources that are shared across tests.
• @AfterClass: Indicates that a method should run once after all the test methods in the class have completed. Like @BeforeClass, this method must be static and is useful for cleaning up shared resources.
• @Disabled: Used to temporarily disable a test method. This is useful when a test is under development or should not be executed for some reason.
• @Tag: Used to categorize tests into groups for easier execution and filtering. For example, you might tag certain tests as “fast” or “slow” to run only specific groups.
• @Nested: Marks a class as a nested test class. It allows organizing tests hierarchically, making it easier to group related tests.
• @Timeout: Sets a time limit for a test method. If the test takes longer than the specified duration, it is considered failed.

Summary of JUnit Annotations

Annotation	Description
@Test	Marks a method as a test case that should be executed by JUnit.
@Before	Indicates that a method should run before each test method.
@After	Indicates that a method should run after each test method.
@BeforeClass	Marks a static method to run once before all test methods in the class.
@AfterClass	Marks a static method to run once after all test methods in the class.
@Disabled	Disables a test method from being executed.
@Tag	Categorizes tests for filtering and grouping purposes.
@Nested	Marks a class as a nested test class, allowing tests to be organized hierarchically.
@Timeout	Sets a time limit for a test method. The test fails if it exceeds the time limit.