JUnit is a unit testing framework for Java. It helps us write and run test cases to check if our code works correctly. Mainly used to test small parts like methods or classes.

• @Test – Marks a method as a test case.
• @Before – Runs before every test case.
• @After – Runs after every test case.
• @BeforeClass – Runs once before all test cases (must be static).
• @AfterClass – Runs once after all test cases (must be static).
• @Ignore – Skips the test case from execution.

JUnit Annotation Execution Order:

• @BeforeClass
• @Before
• @Test
• @After
• @AfterClass

• assertEquals(expected, actual) – Passes if both values are equal.
• assertTrue(condition) – Passes if condition is true.
• assertFalse(condition) – Passes if condition is false.
• assertNull(object) – Passes if object is null.
• assertNotNull(object) – Passes if object is not null.
• fail() – Fails the test immediately when called.

@Ignore is used to skip a test method temporarily during test execution without deleting it.

In JUnit, we use the @RunWith(Suite.class) and @Suite.SuiteClasses({}) annotations to run multiple test classes together as a test suite. It allows grouping of test classes and executing them as one unit.