Test Driven Development
Embrace Uncertainty
Naresh Jain
Twitter: @nashjain
http://blogs.agilefaqs.com
Licensed Under Creative Commons by Naresh Jain
Friday, October 2, 2009 1

TDD Rhythm
Test, Code, Refactor
Friday, October 2, 2009 2

TDD Rhythm
Test, Code, Refactor
Add a Test
Friday, October 2, 2009 2

TDD Rhythm
Test, Code, Refactor
Add a Test
Run the Test
Friday, October 2, 2009 2

TDD Rhythm
Test, Code, Refactor
Add a Test
Pass
Run the Test
Friday, October 2, 2009 2

TDD Rhythm
Test, Code, Refactor
Add a Test
Pass
Run the Test
Fail
Friday, October 2, 2009 2

TDD Rhythm
Test, Code, Refactor
Add a Test
Pass
Run the Test
Fail
Make a little
change
Friday, October 2, 2009 2

TDD Rhythm
Test, Code, Refactor
Add a Test
Pass
Run the Test
Fail
Make a little
change
Run the Test
Friday, October 2, 2009 2

TDD Rhythm
Test, Code, Refactor
Add a Test
Pass
Run the Test
Fail
Make a little
change
Fail
Run the Test
Friday, October 2, 2009 2

TDD Rhythm
Test, Code, Refactor
Add a Test
Pass
Run the Test
Fail
Make a little
change
Fail
Run the Test
Pass
Friday, October 2, 2009 2

TDD Rhythm
Test, Code, Refactor
Add a Test
Pass
Run the Test
Fail
Make a little
change
Fail
Run the Test
Pass
Refactor
Friday, October 2, 2009 2

TDD Rhythm
Test, Code, Refactor
Add a Test
Pass
Run the Test
Fail
Make a little
change
Fail
Run the Test
Pass
Refactor
Friday, October 2, 2009 2

TDD Rhythm
Test, Code, Refactor
Add a Test
Pass
Run the Test
Fail
Make a little
change
Fail
Run the Test
Pass
Refactor
Friday, October 2, 2009 2

TDD Rhythm
Test, Code, Refactor
Add a Test
Pass
Run the Test
Fail
Make a little
change
Fail
Run the Test
Pass
Refactor
Friday, October 2, 2009 2

But....
Friday, October 2, 2009 3

rk? e?
Ho a Wo m her
wt
oS E xtr probl
e
tar a
t? th ere
Wh Is
o? W
hen
?
ROI?
Pro
duc
tivit
y?
Friday, October 2, 2009 3

Continuum
Friday, October 2, 2009 4

Friday, October 2, 2009 5

Post Agile
New to Agile
Friday, October 2, 2009 5

Post Agile
Expert TDD
New to TDD
Practitioners
New to Agile
Friday, October 2, 2009 5

Me
Friday, October 2, 2009 6

Friday, October 2, 2009 7

Mumbai
Friday, October 2, 2009 8

Friday, October 2, 2009 9

Friday, October 2, 2009 10

We don’t travel like this
Friday, October 2, 2009 11

We are getting there...
Friday, October 2, 2009 12

Tech Talks!
Friday, October 2, 2009 13

Friday, October 2, 2009 14

Friday, October 2, 2009 15

Friday, October 2, 2009 16

Warmup Scenario
Friday, October 2, 2009 17

Friday, October 2, 2009 18

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?
Friday, October 2, 2009 18

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)
Friday, October 2, 2009 18

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.)
Friday, October 2, 2009 18

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]
Friday, October 2, 2009 18

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]
Present back to the group your findings. [3 minutes per group]
Friday, October 2, 2009 18

Acceptance Criteria
and Tests
A critical piece of Agile
Friday, October 2, 2009 19

Acceptance Criteria
Is 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
Friday, October 2, 2009 20

Given [Precondition]
When [Actor + Action]
Then [Observable Result]
Friday, October 2, 2009 21

Acceptance Criteria
Examples (data + scenarios)
Acceptance Tests
Friday, October 2, 2009 22

Acceptance Criteria
+ Examples (data + scenarios)
Acceptance Tests
Friday, October 2, 2009 22

Demo
Roman Numerals to Decimal Conversion Example
Friday, October 2, 2009 23

1 May 1 Jul 1 Sep 1 Nov
Analysis
Design
Implementation
ERD
DFD
DD
ST
Friday, October 2, 2009 24

Business Facing
Are we building the right product?
Are we building the product right?
Technology/Implementation Facing
Friday, October 2, 2009 25

Brian Marick’s
Test Categorization
Business Facing
Supports Programming
Critique product
Technology/Implementation Facing
Friday, October 2, 2009 26

It Helps to think...
Business Facing
Drives Development
Critique product
Technology/Implementation Facing
Friday, October 2, 2009 27

It Helps to think...
Business Facing
Drives Development
Critique product
Unit Testing
Technology/Implementation Facing
Friday, October 2, 2009 27

It Helps to think...
Business Facing
Acceptance Testing
Drives Development
Low-fi prototypes
Critique product
Unit Testing
Technology/Implementation Facing
Friday, October 2, 2009 27

It Helps to think...
Business Facing
Acceptance Testing Exploratory Testing
Drives Development
Low-fi prototypes UI and Usability Testing
Critique product
Unit Testing
Technology/Implementation Facing
Friday, October 2, 2009 27

It Helps to think...
Business Facing
Acceptance Testing Exploratory Testing
Drives Development
Low-fi prototypes UI and Usability Testing
Critique product
Performance Testing
Unit Testing
System Tests
Technology/Implementation Facing
Friday, October 2, 2009 27

Acceptance Test Driven
Friday, October 2, 2009 28

Acceptance Test Driven
Story
Friday, October 2, 2009 28

Acceptance Test Driven
Acceptance
Criteria
Story
Friday, October 2, 2009 28

Acceptance Test Driven
Iteration
Acceptance
Criteria
Story
Friday, October 2, 2009 28

Acceptance Test Driven
Iteration
Automated
Acceptance
Acceptance Tests
Criteria
Story
Friday, October 2, 2009 28

Acceptance Test Driven
Iteration
Automated
Acceptance
Acceptance Tests
Criteria
Automated
Story Unit Test
Friday, October 2, 2009 28

Acceptance Test Driven
Iteration
Automated
Acceptance
Acceptance Tests
Criteria
Automated
Story Unit Test
Automated
Acceptance
Tests
Friday, October 2, 2009 28

Acceptance Test Driven
Iteration
Automated
Acceptance
Acceptance Tests
Criteria
Automated
Story Unit Test
Automated
Acceptance
Tests
Exploratory
Testing
Friday, October 2, 2009 28

Acceptance Test Driven
Iteration
Automated
Acceptance
Acceptance Tests
Criteria
Automated
Story Unit Test
Automated
Acceptance
Tests
Acceptance
Exploratory Criteria
Testing
Friday, October 2, 2009 28

Acceptance Test Driven
Iteration
Automated
Acceptance
Acceptance Tests
Criteria
Automated
Story Unit Test
Automated
UI Tests
Automated
Acceptance
Tests
Acceptance
Exploratory Criteria
Testing
Friday, October 2, 2009 28

Acceptance Test Driven
Iteration
Automated
Acceptance P
Acceptance Tests E
Criteria R
F
O
Automated R
Story Unit Test M T
Automated E E
UI Tests N S
C T
E S
Automated
Acceptance
Tests
Acceptance
Exploratory Criteria
Testing
Friday, October 2, 2009 28

Mike Cohn’s Testing Pyramid
Friday, October 2, 2009 29

Mike Cohn’s Testing Pyramid
GUI
Tests
Friday, October 2, 2009 29

Mike Cohn’s Testing Pyramid
Small in Number
GUI Tools: Selenium, Sahi, Watir, Abbot, Frankenstein
Tests
Friday, October 2, 2009 29

Mike Cohn’s Testing Pyramid
Small in Number
GUI Tools: Selenium, Sahi, Watir, Abbot, Frankenstein
Tests
Acceptance
Tests
Friday, October 2, 2009 29

Mike Cohn’s Testing Pyramid
Small in Number
GUI Tools: Selenium, Sahi, Watir, Abbot, Frankenstein
Tests
Acceptance At least one per story
Tools: Fit, FitNesse, RSpec, Cucumber
Tests
Friday, October 2, 2009 29

Mike Cohn’s Testing Pyramid
Small in Number
GUI Tools: Selenium, Sahi, Watir, Abbot, Frankenstein
Tests
Acceptance At least one per story
Tools: Fit, FitNesse, RSpec, Cucumber
Tests
Unit Tests
Friday, October 2, 2009 29

Mike Cohn’s Testing Pyramid
Small in Number
GUI Tools: Selenium, Sahi, Watir, Abbot, Frankenstein
Tests
Acceptance At least one per story
Tools: Fit, FitNesse, RSpec, Cucumber
Tests
At least one per class or module
Tools: xUnit, TestNG
Unit Tests
Friday, October 2, 2009 29

Acceptance Tests View
UI
Model and Presenter
Business Tier
Data Store
Friday, October 2, 2009 30

Why care about TDD?
Friday, October 2, 2009 31

Friday, October 2, 2009 32

# of Lines of Code?
Friday, October 2, 2009 33

# of Story Points
(estimates)?
Friday, October 2, 2009 34

Friday, October 2, 2009 35

# of Features developed?
Friday, October 2, 2009 35

# of Features tested?
Friday, October 2, 2009 35

# of Features deployed?
Friday, October 2, 2009 35

# of Features used actively?
Friday, October 2, 2009 35

What about Maintenance?
Friday, October 2, 2009 36

Stay away from (time
hungry) debugger
Friday, October 2, 2009 37

Manual (monkey)
Checking by
Developers and Tester
Friday, October 2, 2009 38

Maintain Focus
Friday, October 2, 2009 39

Reduce Wastage: Hand Overs
Friday, October 2, 2009 40

Communication
Friday, October 2, 2009 41

Living, up-to-date
specification
Friday, October 2, 2009 42

Communicate Design
Decisions
Friday, October 2, 2009 43

Learning:
Listen to your code
Friday, October 2, 2009 44

Baby Steps:
Slow down and think
Friday, October 2, 2009 45

Confidence
Friday, October 2, 2009 46

Testable Code by Design
+ Safety Net
Friday, October 2, 2009 47

Loosely Coupled Design
Friday, October 2, 2009 48

Refactoring
Friday, October 2, 2009 49

Test Driven Design
Before you take the plunge
Friday, October 2, 2009 50

Evolutionary Design
Friday, October 2, 2009 51

System Metaphor
Friday, October 2, 2009 52

Thin Slicing
Friday, October 2, 2009 53

Interaction Design
Friday, October 2, 2009 54

Tracer Bullets
Friday, October 2, 2009 55

Avatars of TDD
Rule of Diversity
Distrust all claims for “One True Way”
Friday, October 2, 2009 56

Business Facing
Drives Development
Critique product
Inside Out
Outside In
Technology/Implementation Facing
Brian Marick’s Test Categorization
Friday, October 2, 2009 57

Veterinarian
Information System
Friday, October 2, 2009 58

Outside In: ATDD
Fitnesse Document:
Assertions: 17 right, 0 wrong, 0 ignored, 0 exceptions
com.vis.billing.fixtures.PaidCashBill
procedure details on the bill
account details
name cost
account number patient name owner name
Routine Office Visit 250
1001 Fluffy Dave Atkins
Rabies Vaccination 50
procedure details
pay Cash
name cost
patient name? owner name? account number? bill no? payment method? amount paid?
Routine Office Visit 250
Fluffy Dave Atkins 1001 1 Cash 300
Rabies Vaccination 50
bill check paid true
account number? owner name? patient name? total? paid?
1001 Dave Atkins Fluffy 300 false check total 0
Friday, October 2, 2009 59

Outside In: Output
Friday, October 2, 2009 60

ATDD: Another Example
Acceptance 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
end
end
Friday, October 2, 2009 61

Outside In: Output
Friday, October 2, 2009 62

Inside Out: Unit TDD
public class ClinicTest {
private Clinic clinic = new Clinic();
@Test public class BillableTest {
public void amountOnTheReceiptShouldMatchBillableAmount() throws Exception {
Billable billable = new Billable() { private static final Account daveSAccount = new Account(101, "Dave");
public int totalAmount() { return 0; } private static final List<Service> services = new ArrayList<Service>();
};
Account dave = new Account(101, "Dave"); @Test
public void totalBillableAmountShouldBeZeroIfNoServicesAreProvided() {
Receipt rcpt = clinic.payCash(dave, billable); Billable bill = new Bill(daveSAccount, services);
assertEquals("Amount on receipt does match procedure cost", billable.totalAmount(), assertEquals("Total amount is not Zero", 0, bill.totalAmount());
rcpt.getAmount()); }
}
@Test
@Test public void totalBillableAmountShouldBeTotalOfEachServiceProvided() {
public void customerPayesBillableAmountForCashTransaction() throws Exception { services.add(new Procedure("Rabies Vaccination", 250));
final int billableAmount = 56; services.add(new Procedure("Regular office Visit", 50));
class AmountCharged { int charged; };
final AmountCharged charged = new AmountCharged(); Billable bill = new Bill(daveSAccount, services);
Billable billable = new Billable() { assertEquals("Total Amount is not 300", 300, bill.totalAmount());
public int totalAmount() { }
return billableAmount;
} @After
}; public void cleanUp() {
services.clear();
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);
}
}
Friday, October 2, 2009 63

Inside Out: Output
Friday, October 2, 2009 64

Inside Out: Another Example
public 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); @Test
reset(bill); public void shouldHaveZeroAmountDueOnReceiptIfCompletePaymentIsMade() {
} expect(bill.amount()).andReturn(300);
replay(bill);
@Test Receipt receipt = clinic.pay(300, bill, account);
public void shouldMakePaymentsAgainstAnAccount() { verify(bill);
account.paid(bill); assertEquals(300, receipt.amount());
replay(account); assertEquals(0, receipt.amountDue());
clinic.pay(300, bill, account); }
verify(account);
} @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());
}
}
Friday, October 2, 2009 65

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() { @Test
expect(account.isPaymentDue()).andReturn(false); public void shouldCreateABillWithTheTotalCostOfAllTheServices() {
replay(account); IMocksControl control = createControl();
try { Service rabiesVaccination = control.createMock(Service.class);
new Bill(account, null); Service routineVisit = control.createMock(Service.class);
} catch (NoPaymentDueException e) { services.add(rabiesVaccination);
// expected services.add(routineVisit);
}
expect(account.isPaymentDue()).andReturn(true);
verify(account);
expect(account.unpaidServices()).andReturn(services);
} bill();
@After expect(rabiesVaccination.cost()).andReturn(250);
public void cleanUp() { expect(routineVisit.cost()).andReturn(50);
services.clear();
} control.replay();
assertEquals(300, bill.amount());
control.verify();
}
private void bill() throws NoPaymentDueException {
replay(account);
bill = new Bill(account, null);
verify(account);
}
}
Friday, October 2, 2009 66

Inside Out: Output
Friday, October 2, 2009 67

Coffee Vending Machine
How would you develop it?
Friday, October 2, 2009 68

Feedback
Friday, October 2, 2009 69

Friday, October 2, 2009 70

Friday, October 2, 2009 71

Friday, October 2, 2009 72

Visualizing Proficiency
Industrial Logic’s
e-learning
Automated Analysis of Lab Exercises
http://industriallogic.com/elearning/
Friday, October 2, 2009 73

Friday, October 2, 2009 74

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Friday, October 2, 2009 78

Friday, October 2, 2009 79

Tools & Practices
Friday, October 2, 2009 80

Pair Programming
Friday, October 2, 2009 81

Continuous Integration
Friday, October 2, 2009 82

Friday, October 2, 2009 83

Coding Convention
+
Static Code Analysis
Friday, October 2, 2009 84

Checkstyle
Friday, October 2, 2009 85

Code Coverage
Friday, October 2, 2009 86

Cobertura
Friday, October 2, 2009 87

DB Management
Friday, October 2, 2009 88

Migrate4j
Bering
Friday, October 2, 2009 89

Questions?
naresh@agilefaqs.com
Friday, October 2, 2009 90