JUnit testing framework usage example

Below steps demonstrates usage of JUnit testing framework for unit testing Java Program.

1) Download JUnit jar library from JUnit website [http://www.junit.org/]

• https://github.com/downloads/KentBeck/junit/junit-4.9.jar

2) Add external library to your Eclipse Project

3) Using JUnit API assert existing implementation by creating test case

import junit.framework.TestCase;

public class EmpolyeeHandlerTest extends TestCase {

    

     public void testGetAnnualPerks() {

          EmployeeHandler handler = new EmployeeHandler();

          //assertEquals(expected Value, Actual Value);

          assertEquals(400.0, handler.getAnnualPerks(1));

          assertEquals(900.0, handler.getAnnualPerks(2));

          assertEquals(1600.0, handler.getAnnualPerks(3));

          assertEquals(3000.0, handler.getAnnualPerks(4));

     }

}

4) Existing implementation which is to be unit tested with above test class

public class EmployeeHandler {

     public double getAnnualPerks(int empGrade) {

          int salary = 0; // local variable

          double perks = 0; // local variable

         

          switch (empGrade) {

               case 1 :

                    salary = 4000;

                    perks = salary * 0.10;

                    break;

               case 2 :

                    salary = 6000;

                    perks = salary * 0.15;

                    break;

               case 3 :

                    salary = 8000;

                    perks = salary * 0.20;

                    break;

               case 4 :    

                    salary = 10000;

                    perks = salary * 0.30;

                    break;

               default :

                    System.out.println("Invalid Employee grade.");

          }

    

          return perks;

     }

}
5) Run above test case from Eclipse to get below output