Principles of Object Oriented Programming Practical session 2 – part A

Testing The importance of testing:  Tests represent requirements:  Ensure that product works as user expected.  Reduced costs:  By discover defects early in the software life cycle.  Program Managers often say: “Testing is too expensive.”  Not testing is even more expensive  You’re going to spend about half of your development budget on testing, whether you want to or not.

 White-box testing : Tests internal structures or workings of a program  Black-box testing : Examining functionality without any knowledge of internal implementation.  Grey-box testing :  Involves having knowledge of internal data structures and algorithms for purposes of designing tests, while executing those tests at the user, or black-box level. Testing methods

 Unit testing: The testing of individual software components.  Integration testing: Integration testing is any type of software testing that seeks to verify the interfaces between components against a software design.  System testing: Tests a completely integrated system to verify that it meets its requirements.  Acceptance testing: Test conducted to determine if the requirements of a specification or contract are met. Testing levels

 JUnit is a testing framework written by Erich Gamma and Kent Beck.  It is used by developers who implement unit tests in Java.  JUnit is Open Source Software. JUnit

 JUnit is build in eclipse.  To setup JUnit in Eclipse:  Open eclipse.  Right click on project.  Click on property.  Build Path.  Configure Build Path and add the junit-4 in the libraries using “Add Libraries…” button. Using JUnit

 To test a project:  Create a test class on a different package in the project.  Import the JUnit package: import org.junit.*  Write test using the tags: Setup the testing object. The code testing the code. Cleaning up after the test end.  Use Asserts function to test the code. Creating a tests

package main_pkg; public class Operations { public double div(double x, double y) { if (y == 0) throw new RuntimeException("Can't divide by zero"); return x/y; } { A code to test:

package tests; import main_pkg.Operations; import org.junit.Assert; import org.junit.Before; import org.junit.Test; public class OperationsTests { private Operations public void createSub() { obj = new Operations(); public void testDiv1() { Assert.assertEquals("8 / 4 should be 2", obj.div(8, 4), 2, 0.01); public void testDiv2() { try { obj.div(10, 0); Assert.fail("Exception expected"); { catch (Exception e) { // Success } } Writing tests import org.junit.*;