Objectives: Test Options JUnit Testing Framework TestRunners Test Cases and Test Suites Test Fixtures JUnit

What is Unit Testing?  Writing tests for small, discretely-defined portions of code  Run and Analyze the Tests  Make it part of Development Process  Run on a Regular Basis  Result is better confidence in the quality of Code

Why Unit Test?  Increase Robustness of your Code  Reduce the time and cost of delivering a system  Measure your progress of development  Early discovery of regressions  Identify unintended side effects  Focus your development effort

What is JUnit?  Open source framework for unit testing written by Erich Gamma and Kent Beck.  Assertions for testing expected results  Test fixtures for sharing common test data  Test suites for easily organizing and running tests  Based on Annotations  Textual test runner  org.junit.runner.JUnitCore

JUnit Goals  Provide a framework that encourages developers to write tests  Overcome the “lack of time” argument  Use familiar tools  Create tests that retain their value over time  Test should be reusable by others  Leverage existing tests to create new ones  Test Fixtures

Writing Testing Code  Debugger Statements  Runtime Expressions  Print Statements  Test Scripts  Tests as Objects  Familiar to Developers  Established Methodology

Writing a Test Case  Steps for running a Test Case using JUnit  Define a class to contain test methods  Annotate test methods  To check a value, call assertTrue() and pass a boolean that is true if the test succeeds

Simple Test Case import java.util.*; import org.junit.Test; import static org.junit.Assert.*; public class MathTest public void addition() { double result= 3 + 2; assertTrue(result == 5.0); }

Alternative Ways to Execute the Test  Test Suite import org.junit.runner.*; import org.junit.runners.*; import public class AllTests {... // this class can be empty }

TestCase Lifecycle  Methods marked  Invoked prior to each test  Methods marked  Invoked after each test  For each test method in a TestCase class, the JUnit framework performs these basic steps:  Create a new instance of the TestCase class  method(s) of the TestCase  Invoke the test method  method(s) of the TestCase  Release the reference to the TestCase instance, which then becomes garbage

Class Scoped set-up and tear-down  static methods marked  Run exactly once before all the test methods in the class run  static methods marked  Run exactly once after all the test methods in the class run  For expensive initializations and clean-ups  Database connections  Network connections  Instead of re-creating before each and every test, create it only once and tear it down once  Test cases can run much faster

Fixtures  Used to establish baseline testing environment  Can be shared by many different tests and test cases.  To create a fixture:  Create a TestCase class  Add an instance variable for each part of the fixture  method to initialize the variables  method to release any permanent resources you allocated in initialization

Fixture Example import java.util.*; import org.junit.*; import static org.junit.Assert.*; public class MathTest { protected double fVal1; protected double public void setUp() { fVal1 = 2.0; fVal2 = 3.0; public void addition() { double result= fVal1 + fVal2; assertTrue(result == 5.0); } }

Test Code  Contained within test cases  Test methods must be public, must take no arguments, and must return void.  Typically named testXXX public void testEmptyCollection(){} public void testOneItemCollection(){}

Determining Success or Failure  Part of testing is to run and analyze the test to determine success or failure  Assert Methods throw AssertionError  assertEquals()  assertTrue()  assertNotNull()  Several overloaded versions in org.junit.Assert  Uncaught exceptions are captured by test runner

Testing Exceptions  Use annotation to declare expected exceptions  If exception is not thrown (or a different exception is thrown), the test will public void divideByZero() { int n = 2/0; }

Ignored Tests  Use annotation to declare ignored tests  For excessively complex or slow tests not currently public void testInternet() { // screenscrape all web pages }

Timed Tests  Use annotation to declare timeout parameter  If test takes longer than the specified number of milliseconds to run, the test public void retrieveData() { // database access }

Test Design  Create Repeatable Tests  Run Unit Test after code modification  Guard against regressions  “code a little, test a little”  Write tests as you develop  Write tests to help you debug  Constantly check your tests against your code

What to test  Critical Areas of your code  Parts that are most likely to break  get/set methods?  Forwarding methods?  JSP with no business logic?  Refactored Code  Code that changes the value of an object or creates some kind of side effect.

Test Suite  Runs more than one test at the same time  Programmatic container for TestCase classes  Runs test cases as a logical group  Can contain other TestSuites

Creating a Test Suite import org.junit.runner.*; import org.junit.runners.*; import AnotherTest.class}) public class AllTests public static public static void… }

Test Runner - JUnitCore  Executes tests  Text output  Period (.) indicates passed test .E indicates failed test .I indicates ignored test  JUnitCore will run any number of test classes java –classpath.;junit-4.4.jar org.junit.runner.JUnitCore TestA TestB TestC

Test Runner Output  Text Output

Summary  Test Options  JUnit Testing Framework  TestRunners  Test Cases and Test Suites  Test Fixtures