TDD Overview

Test Driven DevelopmentEmbrace Uncertainty

Naresh JainTwitter: @nashjain

http://blogs.agilefaqs.com

Licensed Under Creative Commons by Naresh Jain1Friday, October 2, 2009

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http://agilefaqs.com/nareshjain.html

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TDD RhythmTest, Code, Refactor

2Friday, October 2, 2009

Add a Test



Add a Test

Run the Test



Add a Test

Run the TestPass



Add a Test

Run the Test

Fail

Pass



Add a Test

Run the Test

Make a little change

Fail

Pass



Add a Test

Run the Test


Run the Test

Fail

Pass



Add a Test

Run the Test


Run the Test

Fail

Fail

Pass



Add a Test

Run the Test


Run the Test

Fail

Pass

Fail

Pass



Add a Test

Run the Test


Run the Test

Refactor

Fail

Pass

Fail

Pass



Add a Test

Run the Test


Run the Test

Refactor

Fail

Pass

Fail

Pass



Add a Test

Run the Test


Run the Test

Refactor

Fail

Pass

Fail

Pass



Add a Test

Run the Test


Run the Test

Refactor

Fail

Pass

Fail

Pass



But....


ROI?

Is there a p

roblem here?

Extra Work?

How to Start?Who? When?Productivity?


Continuum



New to Agile

Post Agile


New to Agile

Post Agile

New to TDDExpert TDDPractitioners


Me



Mumbai8Friday, October 2, 2009



We don’t travel like this


We are getting there...


Tech Talks!





Warmup Scenario



Pick one scenario and in relation to your scenario, what are the specific observable results that will tell you that the activity has been successfully completed?



Going out for Movie (THX sound and Digital projection)




Going out for meal (one veg.)





Going shopping ($50)[10 Minutes]





Going shopping ($50)[10 Minutes]

Present back to the group your findings. [3 minutes per group]


Acceptance Criteria and Tests

A critical piece of Agile


Acceptance CriteriaIs a set of conditions that the Story must meet for it to be accepted as complete

Is typically provided by the customer or product owner.

Is not a replacement for conversation.

Is one of the results of the conversation

Acceptance Criteria are NOT tests


Given [Precondition]

When [Actor + Action]

Then [Observable Result]


Acceptance Criteria

Examples (data + scenarios)

Acceptance Tests


Acceptance Criteria

Examples (data + scenarios)

Acceptance Tests

+


DemoRoman Numerals to Decimal Conversion Example


Analysis

Design

Implementation

DFDERD

DDST

1 May 1 Nov1 Jul 1 Sep


Are we building the right product?

Are we building the product right?

Business Facing

Technology/Implementation Facing


Brian Marick’s Test Categorization

Business Facing


Supp

orts

Pro

gram

min

gC

ritique product


Business Facing


Dri

ves

Dev

elop

men

t Critique product

It Helps to think...


Business Facing


Dri

ves

Dev

elop

men

t Critique product

Unit Testing



Business Facing


Dri

ves

Dev

elop

men

t Critique product

Unit Testing

Acceptance Testing Low-fi prototypes



Business Facing


Dri

ves

Dev

elop

men

t Critique product

Unit Testing


Exploratory TestingUI and Usability Testing



Business Facing


Dri

ves

Dev

elop

men

t Critique product

Unit Testing


Exploratory TestingUI and Usability Testing

Performance TestingSystem Tests



Acceptance Test Driven



Story



Story

Acceptance Criteria


Acceptance Test DrivenIteration

Story

Acceptance Criteria



Automated Acceptance

Tests

Story

Acceptance Criteria




Tests

Story

Acceptance Criteria

Automated Unit Test




Tests

AutomatedAcceptance

Tests

Story

Acceptance Criteria

Automated Unit Test




Tests

AutomatedAcceptance

Tests

Story

Acceptance Criteria

ExploratoryTesting

Automated Unit Test




Tests

AutomatedAcceptance

Tests

Story

Acceptance Criteria

Acceptance Criteria

ExploratoryTesting

Automated Unit Test




Tests

AutomatedAcceptance

Tests

Story

Acceptance Criteria

Acceptance Criteria

ExploratoryTesting

Automated UI Tests

Automated Unit Test




Tests

AutomatedAcceptance

Tests

Story

Acceptance Criteria

Acceptance Criteria

ExploratoryTesting

Automated UI Tests

TESTS

PERFORMENCE

Automated Unit Test


Mike Cohn’s Testing Pyramid



GUITests



GUITests

Small in NumberTools: Selenium, Sahi, Watir, Abbot, Frankenstein



AcceptanceTests

GUITests




AcceptanceTests

GUITests


At least one per storyTools: Fit, FitNesse, RSpec, Cucumber



Unit Tests

AcceptanceTests

GUITests





Unit Tests

AcceptanceTests

GUITests



At least one per class or moduleTools: xUnit, TestNG


Business Tier

View

Data Store

Acceptance Tests

UI

Model and Presenter


Why care about TDD?



# of Lines of Code?


# of Story Points (estimates)?



# of Features developed?


# of Features tested?


# of Features deployed?


# of Features used actively?


What about Maintenance?


Stay away from (time hungry) debugger


Manual (monkey) Checking by

Developers and Tester


Maintain Focus


Reduce Wastage: Hand Overs


Communication


Living, up-to-date specification


Communicate Design Decisions


Learning:Listen to your code


Baby Steps:Slow down and think


Confidence


Testable Code by Design+ Safety Net


Loosely Coupled Design


Refactoring


Test Driven DesignBefore you take the plunge


Evolutionary Design


System Metaphor


Thin Slicing


Interaction Design


Tracer Bullets


Avatars of TDDRule of Diversity

Distrust all claims for “One True Way”


Business Facing


Dri

ves

Dev

elop

men

t Critique product

Outside In

Inside Out

Brian Marick’s Test Categorization


Veterinarian Information System


Outside In: ATDDFitnesse Document:Assertions: 17 right, 0 wrong, 0 ignored, 0 exceptions

com.vis.billing.fixtures.PaidCashBill

account details

account number patient name owner name

1001 Fluffy Dave Atkins

procedure detailsname costRoutine Office Visit 250

Rabies Vaccination 50

billaccount number? owner name? patient name? total? paid?1001 Dave Atkins Fluffy 300 false

procedure details on the billname costRoutine Office Visit 250

Rabies Vaccination 50

pay Cash

patient name? owner name? account number? bill no? payment method? amount paid?

Fluffy Dave Atkins 1001 1 Cash 300

check paid true

check total 0


Outside In: Output


ATDD: Another ExampleAcceptance test:class FluffyTest < Test::Unit::TestCase def test_examination_and_shots vet = Veterinarian.new clinic = Clinic.new "Main Line health" dave = Owner.new "Dave" fluffy = Patient.new "Fluffy" dave.has fluffy visit = clinic.visit(fluffy, vet) do |v| v.procedure "Rabies vaccination", 50 end invoice = visit.invoice assert_equal invoice.to_s, <<-INVOICE Routine visit: $200 Rabies vaccination: $50 Total: $250 INVOICE receipt = clinic.pay_for visit, 100 assert_equal receipt.to_s, <<-RECEIPT Paid $100 for Routine visit Paid $0 for Rabies vaccination Outstanding: $150 RECEIPT endend


Outside In: Output


Inside Out: Unit TDDpublic class ClinicTest { private Clinic clinic = new Clinic();

@Test public void amountOnTheReceiptShouldMatchBillableAmount() throws Exception { Billable billable = new Billable() { public int totalAmount() { return 0; } }; Account dave = new Account(101, "Dave");

Receipt rcpt = clinic.payCash(dave, billable); assertEquals("Amount on receipt does match procedure cost", billable.totalAmount(), rcpt.getAmount()); }

@Test public void customerPayesBillableAmountForCashTransaction() throws Exception { final int billableAmount = 56; class AmountCharged { int charged; }; final AmountCharged charged = new AmountCharged();

Billable billable = new Billable() { public int totalAmount() { return billableAmount; } };

Account dave = new Account(101, "Dave") { public void charge(int amount) { charged.charged = amount; } };

clinic.payCash(dave, billable); assertEquals("Account is not charged billable amount", billableAmount,charged.charged); }}

public class BillableTest {

private static final Account daveSAccount = new Account(101, "Dave"); private static final List<Service> services = new ArrayList<Service>();

@Test public void totalBillableAmountShouldBeZeroIfNoServicesAreProvided() { Billable bill = new Bill(daveSAccount, services); assertEquals("Total amount is not Zero", 0, bill.totalAmount()); }

@Test public void totalBillableAmountShouldBeTotalOfEachServiceProvided() { services.add(new Procedure("Rabies Vaccination", 250)); services.add(new Procedure("Regular office Visit", 50));

Billable bill = new Bill(daveSAccount, services);

assertEquals("Total Amount is not 300", 300, bill.totalAmount()); }

@After public void cleanUp() { services.clear(); }}


Inside Out: Output


Inside Out: Another Examplepublic class ChargeAccountForServices { private static final Billable bill = createMock(Billable.class); private static final Accountable account = createMock(Accountable.class); private static final Clinic clinic = new Clinic();

@Before public void setUp() { reset(account); reset(bill); }

@Test public void shouldMakePaymentsAgainstAnAccount() { account.paid(bill); replay(account); clinic.pay(300, bill, account); verify(account); }

@Test public void shouldHaveZeroAmountDueOnReceiptIfCompletePaymentIsMade() { expect(bill.amount()).andReturn(300); replay(bill); Receipt receipt = clinic.pay(300, bill, account); verify(bill); assertEquals(300, receipt.amount()); assertEquals(0, receipt.amountDue()); }

@Test public void shouldDisplayAmountDueOnTheReceiptIfIncompletePaymentIsMade() { expect(bill.amount()).andReturn(500); replay(bill); Receipt receipt = clinic.pay(300, bill, account); verify(bill); assertEquals(300, receipt.amount()); assertEquals(200, receipt.amountDue()); }}


public class CreateBillForClientAccount { private static final List<Service> services = new ArrayList<Service>(); private static final Accountable account = createMock(Accountable.class); private Bill bill;

@Before public void setUp() { reset(account); }

@Test public void shouldThrowExceptionIfAccountIsNotDueForPayment() { expect(account.isPaymentDue()).andReturn(false); replay(account); try { new Bill(account, null); } catch (NoPaymentDueException e) { // expected } verify(account); }

@After public void cleanUp() { services.clear(); }

@Test public void shouldCreateABillWithTheTotalCostOfAllTheServices() { IMocksControl control = createControl(); Service rabiesVaccination = control.createMock(Service.class); Service routineVisit = control.createMock(Service.class); services.add(rabiesVaccination); services.add(routineVisit);

expect(account.isPaymentDue()).andReturn(true); expect(account.unpaidServices()).andReturn(services); bill();

expect(rabiesVaccination.cost()).andReturn(250); expect(routineVisit.cost()).andReturn(50);

control.replay();

assertEquals(300, bill.amount()); control.verify(); }

private void bill() throws NoPaymentDueException { replay(account); bill = new Bill(account, null); verify(account); }}


Inside Out: Output


Coffee Vending MachineHow would you develop it?


Feedback





Visualizing ProficiencyIndustrial Logic’s

e-learningAutomated Analysis of Lab Exerciseshttp://industriallogic.com/elearning/


http://industriallogic.com/elearning/

http://industriallogic.com/elearning/







Tools & Practices


Pair Programming


Continuous Integration



Coding Convention+

Static Code Analysis


Checkstyle


Code Coverage


Cobertura


DB Management


BeringMigrate4j


Questions?

[email protected]


mailto:[email protected]

mailto:[email protected]