unit testing video€¦ · test driven development (tdd) • coding and testing are done in...

UnitTesting

Hans-PetterHalvorsen,M.Sc.

Contents

1.WhatisTesting?– ShortIntroductiontoTesting

2.WhatisUnitTesting?3. UnitTestinginVisualStudio

IntroductiontoTesting


RequirementsAnalysis

Design

Implementation

Testing

Maintenance

PlanningDeployment

SRS

SDD

STD

Code

InstallationGuides

UserGuides

GanttChart

withERDiagram,UMLDiagrams,CADDrawings

TestDocumentation

SoftwareRequirementsSpecifications

SoftwareDesignDocumentsSystemDocumentation

SoftwareTestPlan(STP)

ProjectPlanning

End-UserDocumentation

SystemDocumentation

SoftwareTestDocumentation

SDPSoftwareDevelopment

Plan

GanttChart

TheSoftwareDevelopment

Lifecycle(SDLC)

WhyFindBugsearly?

SoftwareDevelopmentLifeCycle(SDLC)

ValidationTesting DefectTesting

Testing

DemonstratetotheDeveloperandtheCustomerthattheSoftwaremeetsitsRequirements.

I.Sommerville,SoftwareEngineering,10ed.:Pearson,2015.

CustomSoftware:Thereshould beatleastonetestforeveryrequirement intheSRSdocument.GenericSoftware:Thereshould betestsforallofthesystemfeaturesthatwillbeincluded intheproductrelease.

Find inputsorinput sequenceswherethebehaviorofthesoftwareisincorrect,undesirable,ordoesnotconformtoitsspecifications.Thesearecausedbydefects(bugs) inthesoftware.

TestCategoriesBlack-boxvs.White-boxTesting

White-boxTesting:Youneedtohaveknowledgeofhow(DesignandImplementation)thesystemisbuilt

Black-boxTesting:Youneednoknowledgeofhowthesystemiscreated.

TypicallydonebyDevelopers,etc

LevelsofTesting

UnitTesting

IntegrationTesting

SystemTesting

AcceptanceTesting

Anymodule,program,objectseparatelytestable

Interfacebetweencomponents; interactionswithothersystems(OS,HW,etc)

Thebehaviorofthewholeproduct(system)asdefinedbythescopeoftheproject

Istheresponsibility ofthecustomer– ingeneral.Thegoalistogainconfidence inthesystem;especiallyinitsnon-functional characteristics

LevelsofTestingUnitTesting:Testeachpartsindependentlyandisolated

IntegrationTesting:Makesurethatdifferentpiecesworktogether.TesttheInterfacesbetweenthedifferentpieces.Interactionwithothersystems(Hardware,OS,etc.)

SystemTesting:Testthewholesystem

RegressionTesting:Testthatitstillworksafterachangeinthecode,i.e.,runallUnitTests,etc.

LevelsofTesting

UnitTesting

RegressionTesting

IntegrationTesting

System/ValidationTesting

AcceptanceTesting

Start

Finish

Requirements&DesignStartDevelopment

UnitTestsarewrittenbytheDevelopersaspartoftheProgramming.EachpartisdevelopedandUnittestedseparately(EveryClassandMethod inthecode)

TheCustomerneeds totestandapprove thesoftwarebeforehecantakeitintouse.FAT/SAT.

SystemtestingistypicallyBlack-boxTeststhatvalidatetheentiresystemagainstitsrequirements, i.eCheckingthatasoftwaresystemmeetsthespecifications

Integrationtestingmeansthesystemisputtogetherandtestedtomakesureeverythingworkstogether.

Regressiontestingistestingthesystemtocheckthatchangeshavenot“broken”previouslyworkingcode.BothManually&Automatically(Re-runUnitTests)

UnitTesting


WhatareUnitTests• UnitTesting(orcomponenttesting)referstoteststhatverifythefunctionalityofaspecificsectionofcode,usuallyatthefunctionlevel.

• Inanobject-orientedenvironment,thisisusuallyattheclassandmethodslevel.

• UnitTestsaretypicallywrittenbythedevelopersaspartoftheprogramming

• Automaticallyexecuted(e.g.,VisualStudioandTeamFoundationServerhavebuilt-infunctionalityforUnitTesting)

TestDrivenDevelopment(TDD)• CodingandTestingaredoneinparallel• TheTestsarenormallywrittenbeforetheCode• IntroducedaspartofeXremeProgramming(XP)(anAgilemethod)

• UnitTestsareimportantpartofSoftwareDevelopmenttoday– eitheryouareusingTDDornot

UnitTestsFrameworksUnitTestsFrameworkareusuallyintegratedwiththeIDE• VisualStudioUnitTestFramework.UnitTestsarebuilt intoVisualStudio (noadditional

installationneeded)Others:• JUnit (Java)

– JUnitisaunittestingframeworkfortheJavaprogramminglanguage.• NUnit (.NET)

– NUnit isanopensourceunittestingframeworkforMicrosoft.NET.ItservesthesamepurposeasJUnitdoes intheJavaworld

• PHPUnit (PHP)• LabVIEWUnitTestFrameworkToolkit• etc.

Allofthemworkinthesamemanner– butwewillusetheVisualStudioUnitTestFramework

http://en.wikipedia.org/wiki/Visual_Studio_Unit_Testing_Framework

BasicConceptinUnitTesting

...

Assert.AreEqual(expected, actual, 0.001, ”Test failed because...");

ThebasicconceptinUnitTestingistoCompare theresultswhenrunningtheMethodswithsomeInputData(“Actual”)withsomeKnownResults(“Expected”)

Example:

CompareErrormargin Errormessageshown if

theTestfails

AllUnitTestsFrameworkhavetheAssertClass

TheAssertClasscontainsdifferentMethods thatcanbeusedinUnitTesting

UnitTests– BestPractice• AUnitTestmustonlydoonething• UnitTestmustrunindependently• UnitTestsmustnotbedependontheenvironment• TestFunctionalityratherthanimplementation• Testpublicbehavior;privatebehaviorrelatestoimplementation

details• AvoidtestingUIcomponents• UnitTestsmustbeeasytoreadandunderstand• CreaterulesthatmakesureyouneedtorunUnitTests(andthey

needtopass)beforeyouareallowedtoCheck-inyourCodeintheSourceCodeControlSystem

http://www.uio.no/studier/emner/matnat/ifi/INF5530

UnitTestinginVisualStudio


UnitTestinginVisualStudio• VisualStudiohavebuilt-infeaturesforUnitTesting

• Weneedtoincludea“TestProject”inourSolution

TestMethodRequirements

Atestmethodmustmeetthefollowingrequirements:• Themethodmustbedecoratedwiththe[TestMethod]attribute.

• Themethodmustreturnvoid.• Themethodcannothaveparameters.

Example


UnitTestinginVisualStudio

ConverttoFahrenheit

𝑇" =95𝑇& + 32

AsimplesketchoftheUserInterface:

ConversionFormula:

CreatethefollowingApplication (e.g.,WinForm ApporASP.NETApp)

Celsius:22 ℃ Convert 71,6 ℉

Fahrenheit:

UserInterface

CreateyourGUI

Add Class

Class

𝑇" =95𝑇& + 32

public class TemperatureConvert{

public double CelciusToFahrenheit(double Tc){

double Tf;

Tf = 9/5 * Tc + 32;

return Tf;}

}

CreateyourCode

using System;using System.Windows.Forms;

namespace TemperatureApp{

public partial class Form1 : Form{

public Form1(){

InitializeComponent();}

private void btnConvert_Click(object sender, EventArgs e){

TemperatureConvert temperature = new TemperatureConvert();

double temperatureFahrenheit;double temperatureCelcius;

temperatureCelcius = Convert.ToDouble(txtCelsius.Text);

temperatureFahrenheit = temperature.CelciusToFahrenheit(temperatureCelcius);

txtFahrenheit.Text = temperatureFahrenheit.ToString();

}}

}

TestApplication

𝑇" =95𝑇& + 32

𝑇" =95 , 22 + 32

=71.6WegetwrongAnswer!

CreateUnitTestProject

Youhavenow2ProjectsinyourSolutionExplorer

AddReferencetotheCodeunderTest

CreatetheUnitTestCode

using Microsoft.VisualStudio.TestTools.UnitTesting;using TemperatureApp;

namespace UnitTestTemperature{[TestClass]public class UnitTestTempConvert{[TestMethod]public void TestFahrenheitConversion(){TemperatureConvert temperature =new TemperatureConvert();doubletemperatureCelcius =22;doubletemperatureFahrenheitActual;doubletemperatureFahrenheitExpected =71.6;

temperatureFahrenheitActual =temperature.CelciusToFahrenheit(temperatureCelcius);

Assert.AreEqual(temperatureFahrenheitExpected,temperatureFahrenheitActual,0.001,"Temperature conversionnotcorrectly");

}}

}

TestExplorer

StartRunningtheUnitTest

TestResults

Debuggingpublic class TemperatureConvert{


double Tf;

Tf = 9/5 * Tc + 32;

return Tf;

}

}

𝑇" =95𝑇& + 32

ProbablyErrorinFormula?Whatiswrong?

FixingBugspublic class TemperatureConvert

{


double Tf;

Tf = Tc*9/5 + 32;

return Tf;

}

}

𝑇" =95𝑇& + 32

Re-runUnitTest

EverythingWorks!TheTestPassed!

CheckingCodeCoverage

CodeCoverage• Codecoverageisameasureusedinsoftwaretesting.Itdescribes

thedegreetowhichthesourcecodeofaprogramhasbeentested.

• Dependingontheinputarguments,differentpartsofthecodewillbeexecuted.UnitTestsshouldbewrittentocoverallpartsofthecode.

CodeCoverageResults

InthiscasetheUnitTestcovered100%ofthecode.IfweuseIf…Else…orsimiliar,wetypicallyneedtowriteUnitTestforeachIf…Else…inordertocoveralltheCode


UniversityCollegeofSoutheastNorwaywww.usn.no

E-mail:[email protected]:http://home.hit.no/~hansha/