Writing and running JUnit tests in Eclipse

1. File > New > Project > Java Project





2. File > New > Class

package code.more.talk.less;

public class Calculation {

       public int sum (int a, int b) {

              return a + b;

       }

}

File > New > Other > JUnit Test Case





CalculationTest class:

package code.more.talk.less;

import org.junit.After;

import org.junit.Assert;

import org.junit.Before;

import org.junit.Test;

public class CalculationTest {

       @Before

       public void setUp() throws Exception {

              System.out.println("Calling Calculation Test");

       }

       @After

       public void tearDown() throws Exception {

              System.out.println("Finished Calculation Test");

       }

       @Test

       public void test() {

              int result = new Calculation().sum(1, 2);

              Assert.assertEquals(3, result);

       }

}

Change test method expected value and run test again. See the testFailure.

       @Test

       public void test() {

              int result = new Calculation().sum(1, 2);

              Assert.assertEquals(4, result);

       }

File > New > Other > JUnit Test Suite


Add a new method in CalculationTest class:

    @Test

       public void test2() {

              int result = new Calculation().sum(1, 2);

              Assert.assertEquals(3, result);

       }

> Run AllTests class. You'll see two reults for test(failure) and test2(successful ) methods.

•  To ignore a test just add an @Ignore:  You can add it before or after @Test. 
• In test suite you can run more then one class. @SuiteClasses({ class1.class , Class2.class })
• You can add timeout for the test method. Example:

       @Test(timeout=1)

       public void test2() {

              int result = new Calculation().sum(1, 2);

              try {

                     Thread.sleep(1000);

              } catch (InterruptedException e) {

                     e.printStackTrace();

              }

              Assert.assertEquals(3, result);

       }