Annotations, Data Providers & Suite Config

Setup/Teardown Scopes

public class UserServiceTest {

  @BeforeSuite  void initOnce() { /* whole suite, once */ }
  @BeforeClass  void setUpClass() { /* once per class */ }
  @BeforeMethod void setUp() { /* before every test method */ }

  @Test(groups = "smoke")
  public void createsUser() {
    assertNotNull(userService.create("Ada"));
  }

  @AfterMethod  void tearDown() { }
  @AfterClass   void tearDownClass() { }
}

@BeforeMethod/@AfterMethod run per test; @BeforeClass/@AfterClass once per class; @BeforeSuite/@AfterSuite once for the whole run — choose the right scope for correctness (avoid leaking state) and performance (don't repeat expensive setup).

Data Providers — Built-in Parameterized Tests

@DataProvider(name = "emails")
public Object[][] emailData() {
  return new Object[][] {
    { "ada@example.com", true },
    { "not-an-email", false },
  };
}

@Test(dataProvider = "emails")
public void validatesEmail(String email, boolean expected) {
  assertEquals(validator.isValid(email), expected);
}

Groups & testng.xml

<suite name="RegressionSuite" parallel="methods" thread-count="4">
  <test name="SmokeTests">
    <groups>
      <run><include name="smoke"/></run>
    </groups>
    <classes>
      <class name="com.example.UserServiceTest"/>
    </classes>
  </test>
</suite>

groups lets a run include/exclude tagged subsets (fast "smoke" vs. full "regression") without physically reorganizing files. parallel/thread-count configures parallel execution declaratively, no manual threading code.