4) JUnit Аннотации и API

Давайте создадим класс, охватывающий важные аннотации JUnit с помощью простых операторов print, и выполним его с помощью класса тестового прогона:

Step 1) Consider below java class having various methods which are attached to above-listed annotations:

JunitAnnotationsExample.java

package guru99.junit;		

import static org.junit.Assert.assertEquals;				
import static org.junit.Assert.assertFalse;				

import java.util.ArrayList;		

import org.junit.After;		
import org.junit.AfterClass;		
import org.junit.Before;		
import org.junit.BeforeClass;		
import org.junit.Ignore;		
import org.junit.Test;		

public class JunitAnnotationsExample {				

    private ArrayList<String> list;					

    @BeforeClass		
    public static void m1() {							
        System.out.println("Using @BeforeClass , executed before all test cases ");					
    }		

    @Before		
    public void m2() {					
        list = new ArrayList<String>();					
        System.out.println("Using @Before annotations ,executed before each test cases ");					
    }		

    @AfterClass		
    public static void m3() {							
        System.out.println("Using @AfterClass ,executed after all test cases");					
    }		

    @After		
    public void m4() {					
        list.clear();			
        System.out.println("Using @After ,executed after each test cases");					
    }		

    @Test		
    public void m5() {					
        list.add("test");					
        assertFalse(list.isEmpty());			
        assertEquals(1, list.size());			
    }		

    @Ignore		
    public void m6() {					
        System.out.println("Using @Ignore , this execution is ignored");					
    }		

    @Test(timeout = 10)			
    public void m7() {					
        System.out.println("Using @Test(timeout),it can be used to enforce timeout in JUnit4 test case");					
    }		

    @Test(expected = NoSuchMethodException.class)					
    public void m8() {					
        System.out.println("Using @Test(expected) ,it will check for specified exception during its execution");					

    }		

}		

Step 2) let’s create a test runner class to execute above test:

TestRunner.java

package guru99.junit;		

import org.junit.runner.JUnitCore;		
import org.junit.runner.Result;		
import org.junit.runner.notification.Failure;		

public class TestRunner {				
			public static void main(String[] args) {									
      Result result = JUnitCore.runClasses(JunitAnnotationsExample.class);					
			for (Failure failure : result.getFailures()) {							
         System.out.println(failure.toString());					
      }		
      System.out.println("Result=="+result.wasSuccessful());							
   }		
}      	

Expected Result

• All the test cases will be executed one by one, and all print statement can be seen on a console.
• As discussed in above table @Before, @BeforeClass [ method m1() and m2() ] will be executed before each and before all test cases respectively.
• In the same way @after,@afterClass (method m3() and m4()) will be executed after each and after all test cases respectively. @ignore (method m6())will be treated as ignoring the test.

Let’s analyse test cases used in above java class in detail:

1. Consider method m5() as given below :

	@Test		
    public void m5() {					
        list.add("test");					
        assertFalse(list.isEmpty());			
        assertEquals(1, list.size());			
    }		

In above method as you are adding a string in the variable «list» so

• list.isEmpty() will return false.
• assertFalse(list.isEmpty()) must return true.
• As a result, the test case will pass.

As you have added only one string in the list, so the size is one.

• list.size() must return int value as «1» .
• So assertEquals(1, list.size()) must return true.
• As a result, the test case will pass.

2. Consider method m7() as given below :

@Test(timeout = 10)		
    public void m7() {					
        System.out.println("Using @Test(timeout),it can be used to enforce timeout in JUnit4 test case");					
    }		

As discussed above @Test(timeout = 10)annotation is used to enforce timeout in the test case.

3. Consider method m8() as given below :

@Test(expected = NoSuchMethodException.class)				
    public void m8() {					
        System.out.println("Using @Test(expected) ,it will check for specified exception during its execution");					
    
    }		

As discussed above @Test(expected) will check for specified exception during its execution so method m8() will throw «No Such Method Exception.» As a result, the test will be executed with an exception.

As all test cases are passed, this results in a successful test execution.