The document discusses Behavior Driven Development (BDD) and using the NBehave framework to write automated tests for BDD. It provides an overview of BDD and NBehave, including how to create BDD themes and stories with scenarios using the NBehave fluent interface. It also discusses stubbing out behavior, executing tests, comparing BDD to test-driven development, and using NBehave to generate documentation from tests.

1. Behaviour Driven DevelopmentWith NBehaveLinking User Stories and Domain Driven Design to TestingDavid RossW: www.pebblesteps.comE: willmation@gmail.com

2. Behavior Driven DevelopmentTools and techniquesTalk overviewWhat is BDD and how to use NBehave Topics What are high quality requirements?

3. Top down and Bottom up Testing

4. NBehaveUsing libraryUsing the test runnerTop down design with Rhino.Mocks and Nbehave

5. Acceptance testingBehavior Driven DevelopmentAnalysis/Design Methodology by Dan NorthResponse to:confusion about Test Driven Development and Test First DevelopmentLack of rigor around User Stories (Requirements)Projects that generate documentation out of Unit testsCulminated in:the BDD method for writing User StoriesJBehave unit testing framework

6. Behavior Driven DevelopmentBDD is not:a testing framework or style of testinga method for writing testsBDD is:A formalised template for User StoriesAble to create testable User Stories since they are defined in a formal mannerPromotes “security” to a first call citizen in the analysis process

7. Simple Trading applicationExcel spreadsheet replacement

8. Allow Portfolio Manager to decide the percentage split between Cash, Property and Stock within the PortfolioInform the Trader when the Portfolio needs to be rebalanced (ie split in the pie has changed significantly)Allow Operations to standardise Portfolio namesSimple Trading applicationRequirements

9. Test First DevelopmentSmall stepsRed - Analysis/Design HatCreate a test that defines the expected outcome

10. Asking "What I want is...“Green - Creative Hat (Fun part)Experiment/Prototype/Build until the test passesRefactor- EngineeringRefactor, refactor, refactorRedGreenRefactor

11. Test First DevelopmentHow easy is it to use TFD for the followingRequirement/StoryValue = Units * Market PriceIncrease the performance of the User Security module by automatically caching the user’s manager IdThe system must email the Portfolio manager when the Portfolio needs to be rebalancedBuild a web site so that customers can see the performance of the portfolio

12. Test First DevelopmentDo you feel guilty?? Do you write a Failing unit test before every piece of code?Do you write a line of Unit Test code for EVERY line of production code?

13. Behavior DrivenHow do you write a test when you don’t know where you are going? Maybe we need requirements that are easy to write tests for?

14. RequirementsWhat are theyDescribes what a system should do but not how it will be doneContract between the implementation team and the analysis teamAudience is typically the stake holders and not the development team

15. RequirementsPrecise and clear over verboseWe want requirements that Can be tested!!!

16. Are attainable!!!

17. Are traceable into code!!!Requirements GatheringBDD merges two different approachesUser StoriesShort one or two line statement that maps to a few days of development workHighly focusedDomain Driven DesignUbiquitous language – Ensure business terminology permeates into codeClear single definition (within the project) for each business concept - Account has a single meaning

18. BDD User StoriesFormal template for User StoriesStory TemplateAs a [User/Role]I want [Behaviour]so that [I receive benefit]ExampleAs a “Operations staff member”I want “To create a Portfolio”so that“So that it can be traded”

19. BDD User StoriesFormal template for User StoriesScenario TemplateGiven some initial context (the givens),When an event occurs,then ensure some outcomes.ExampleGiven “New portfolio is called Balanced Fund”When “Portfolio already exists”then “Portfolio can no be created”

20. .NET Library for writing automated BDD style testsFluent syntax for building up a BDD Style User StoriesTest runner that executes the stories and generates a report listing the contents of the storiesNBehaveWhat is it?

21. Creating a BDD ThemeCollection of related stories[Theme("Portfolio Maintenance")]public class PortfolioMaintenanceStory{[Story]public void portfolio_create_story () { ... }[Story]public void portfolio_delete_story() { ... }}Reference:NBehave.Narrator.Framework.dll

22. Creating a Story Fluent interface to define the storyvar story = new Story("Create portfolio");story.AsA(“Operations team member") .IWant("To create a new portfolio on behalf of a portfolio manager") .SoThat("the portfolio manager can configure the portfolio and the front office can trade");

23. Creating a ScenarioFluent interface to define the storystory.WithScenario("portfolio does not exist").Given("portfolio name is $name", "Aggressive Fund").When("portfolio does not exist in the database").Then("new portfolio should be created");story.WithScenario("portfolio already exists") .Given("portfolio name is $name", "Aggressive Fund") .When("portfolio already exists in database") .Then("an error should occur");

24. Executing the testWithNBehave runner or mbUnitOuch we get an error???The scenario throws an exception – NBehave isn’t validating any codeUse Pendingstory.WithScenario("portfolio does not exist") .Pending("In progress") .Given("portfolio name is $name", "Aggressive Fund") .When("portfolio does not exist in the database") .Then("new portfolio should be created");

25. Behavior Driven DevelopmentAcross the Project (Story) Life CycleStoryPending ScenarioStubbed Behavior Cycle (Red, Green, Refactor)Real Behavior Cycle (Red, Green, Refactor)Acceptance Test

26. Stubbing out the behaviorWithNBehave and Rhino.MocksSteps to generate an APIGo through the User story and find all the domain objectsCreate a class for each domain object but don’t add stateGo through the User story and create a find all the services that are required (Repositories etc)Create an interface for each service but don’t add any methods

27. Steps to generate the API continued...Slowly implement the storyAdd domain object properties as requiredAdd methods signatures as requiredUse Stubs to explore Inputs/Outputsto the methodsStubbing out the behaviorWithNBehave and Mocking

28. Stubbing exampleCreate a new portfolio storystringportfolioName = "";Portfoliop = null;varportfolioRepository = MockRepository.GenerateStub<IPortfolioRepository>();varportfolioService = MockRepository.GenerateStub<IPortfolioService>();s.WithScenario("portfolio already exists") .Given("portfolio name is $name", "Aggressive Fund", n => {portfolioName= n; p = new Portfolio { Name = portfolioName };portfolioRepository. Stub(x => x.FindPortfolioByName(portfolioName)).Return(p);portfolioService. Stub(X => X.CreatePortfolio(p)).Throw(new ItemExistsException()); })

29. Stubbing exampleCreate a new portfolio story.When("portfolio already exists in database", () => Assert.IsNotNull(portfolioRepository.FindPortfolioByName(portfolioName)) ).Then("new portfolio create should fail", () => Assert.Throws<ItemExistsException>(() => portfolioService.CreatePortfolio(p)) );

30. TFD/BDD ComparisonBehavior DrivenTop down approach

31. Design starting with interfaces (using stubs)

32. Back fill with code later OutputAPI creationTest FirstBottom Up approach

33. Lots of little steps working towards a solution Output TestsUser Acceptance TestNBehavetest cases are compiledMust be created by developers or technical testersAre created at the start of the projectFitnesseUser Acceptance tests are Wiki based and so are dynamicCan be created by end users and business analystsCan be created at the start of the projectBut are only “implemented” by the development late in the SDLC

34. Test Driven DevelopmentDevelopment/Testing PhasesStubsDomain ModelUser StoriesBehaviour Driven DevelopmentGUI TestingFitnessUser AcceptanceTestUnit & Component TestMocksImplemented BehaviourSystemIntegration TestNo Mocks/StubsDeployment Verification Test

35. Fixtures to SpecificationsLoosing Assert from tests. Easier to read? For BAs, yes...Assert.IsTrue(component.IsValid) component.IsValid.ShouldBeTrue()Assert.Contains(s, “hello world”);s.ShouldContains(“hello world”);NBehave contains extension methods for NUnit, mbUnit, xUnit

36. Fixtures to SpecificationsIs it necessary? [TestFixture] [Context][Test] [Specification] [Context]public class When_using_tokenized_stories{[Specification]public void should_replace_token_with_value(){}Stories for BDD. Specifications for focussed tests. The word Test has become a dirty word...

37. Stories to documentationNBehave-Console.exe PebbleSteps.NBehave.Stories.dll /o stories.txtTheme: Trade Compliance Story: Pretrade compliance check As a Trader I want verify a trade against the portfolio before I call the broker So that the portfolio does not move out of compliance Scenario: trade will move portfolio out of compliance Given portfolio with name Balanced Fund And asset allocation pie contains segments Cash 0.4, Stock 0.3, Property 0.3 And allocation pie 0.05 And portfolio contains Stock IBM 1, Cash GBP 1, Property SW5 1Hb 1, Stock BHP 1 When market prices are IBM 1, GBP 1, SW5 1Hb 1, BHP 1 Then portfolio value is 4 And portfolio constituents are Stock totalValue:2 percentOfPie:0.5 lower:0.25 upper:0.35, Cash totalValue:1 percentOfPie:0.25 lower:0.35 upper:0.45, Property totalValue:1 percentOfPie:0.25 lower:0.25 upper:0.35, And portfolio is balanced

38. MSBuild<UsingTaskAssemblyFile="NBehave.MSBuild.dll" TaskName="NBehave.MSBuild.NBehaveTask" /><NBehaveTaskDryRun="false"FailBuild="false"StoryOutputPath="output.xml"TestAssemblies="PebbleSteps.NBehave.Stories.dll" />

39. Still in beta…What’s left to do?The parameter regular expression is on [a-z][A-Z]$example0, $example1 – In story output first parameter is printed twiceGallio integration/replacement of current story runnerCurrent story runner text output formatting is poorHTML or a XSLT for current XML outputOccassional crash in the parsing engine that links text to delegate parameters

40. More informationhttp://nbehave.org/http://www.codeplex.com/NBehavehttp://behaviour-driven.org/http://dannorth.net/Code will be placed onto www.pebblesteps.com Questions?