Difference between BeforeClass and BeforeTest in TestNG

Question

As we know from official TestNG documentation:

@BeforeClass: The annotated method will be run before the first test method in the current class is invoked.

@BeforeTest: The annotated method will be run before any test method belonging to the classes inside the <test> tag is run.

Both the above TestNG annotations look similar in functionality. Can anyone explain the unique difference?

Answer 1

SeleniumAbstractTest.class

public abstract class SeleniumAbstractTest {    @BeforeSuite   public void beforeSuite() {     System.out.println("BeforeSuite");   }    @BeforeTest   public void beforeTest() {     System.out.println("BeforeTest");   }    @BeforeClass   public void beforeClass() {     System.out.println("BeforeClass");   }    @BeforeMethod   public void beforeMethod() {     System.out.println("BeforeMethod");   }    @AfterMethod   public void afterMethod() {     System.out.println("AfterMethod");   }    @AfterClass   public void afterClass() {     System.out.println("AfterClass");   }    @AfterTest   public void afterTest() {     System.out.println("AfterTest");   }    @AfterSuite   public void afterSuite() {     System.out.println("AfterSuite");   }  } 

MyTestClass1.class

public class MyTestClass1 extends SeleniumAbstractTest {    @Test   public void myTestMethod1() {     System.out.println("myTestMethod1");   }    @Test   public void myTestMethod2() {     System.out.println("myTestMethod2");   } } 

MyTestClass2.class

public class MyTestClass2 extends SeleniumAbstractTest {    @Test   public void myTestMethod3() {     System.out.println("myTestMethod3");   }    @Test   public void myTestMethod4() {     System.out.println("myTestMethod4");   } } 

If you have the following Test Suite...

<suite name="Suite">   <test name="Test1" >     <classes>        <class name="MyTestClass2" />     </classes>   </test>    <test name="Test2">     <classes>       <class name="MyTestClass1"/>       <class name="MyTestClass2"/>     </classes>   </test> </suite> 

... then the output [indented for easy reading] will be

BeforeSuite '   BeforeTest '   '   BeforeClass '   '   '   BeforeMethod '   '   '   '   myTestMethod3 '   '   '   AfterMethod '   '   '   BeforeMethod '   '   '   '   myTestMethod4 '   '   '   AfterMethod '   '   AfterClass '   AfterTest '   BeforeTest '   '   BeforeClass '   '   '   BeforeMethod '   '   '   '   myTestMethod1 '   '   '   AfterMethod '   '   '   BeforeMethod '   '   '   '   myTestMethod2 '   '   '   AfterMethod '   '   AfterClass '   '   BeforeClass '   '   '   BeforeMethod '   '   '   '   myTestMethod3 '   '   '   AfterMethod '   '   '   BeforeMethod '   '   '   '   myTestMethod4 '   '   '   AfterMethod '   '   AfterClass '   AfterTest AfterSuite 

Hope it helps :)

Answer 2

@BeforeMethod - executes before every test method e.g. The Method which uses @Test annotation

@BeforeTest - executes only before tag given in testng.xml file.

In a nutshell, @BeforeMethod works on test defined in Java classes. And @BeforeTest works on test defined in testng.xml i.e XML files.