Une introduction au Behavior Driven Development, avec plein d'idées pour tout de suite! et applicable à tout projet. Il sera question: * de passer de l'incompréhension à savoir qu'on ne sait pas * des westerns spaghetti aux Three Amigos, * de reléguer le Comment au second plan pour laisser sa place au Pourquoi! * de rendre des spécifications exécutables * de découvrir qu'un concombre n'est pas qu'un Cucurbitacée aux feuilles tri-lobées * d'automatisation comme outil de non-regression Au cours de cette session, nous expliquerons ce qu'est le BDD. Nous verrons qu'il n'est pas question d'outils ou de tests, mais de collaboration et de discussion entre les différentes parties prenantes: du métier aux développeurs en passant par les testeurs. Cette presentation s'adresse à l'ensemble de ces populations en expliquant l'importance qu'il y a à se comprendre, et qu'il n'est pas nécessaire d'avoir des outils sophistiqués pour avoir des bénéfices immédiats. Nous verrons quelques pratiques de discussion qui permettent d'arriver à une meilleure compréhension et à une description du besoin. Nous verrons aussi comment des exemples concrets permettent de s'assurer d'une compréhension commune et comment ils permettent de construire un langage unique et non ambigu. Nous verrons comment rendre ces spécifications executables en réutilisant les exemples construits précédemment et en les automatisant. Ceux-ci viendront renforcer les tests d'acceptance et devenir des tests de non regressions. Enfin, nous verrons que cette démarche nous permettra d'avoir une documentation vivante et toujours à jour de notre système. Idées pour tout de suite Communication, Clarification par des Exemples concrets, Spécifications exécutables

1. BA CL’
BDDCE QUE C’est
OU
Ce QUE C’est pas…
Arnauld Loyer
@aloyer
2014
du

2. http://pencilink.blogspot.fr/2010/10/iron-man-160-jim-starlin-cover-steve.html
It’s NOT about tools
It’s about Communication and Behavior!
@aloyer

3. http://ungoliantschilde.tumblr.com/post/78793890826/ungoliantschilde-barry-windsor-smith-that
It’s NOT about Testing
It’s about Exploring the Unknown
@aloyer

4. It’s not about Silo!Or Acceptance
Criteria
It’s about
Sharing
and
Understanding
@aloyer

5. It’s about Driven Development!
@aloyer

6. Qu'est ce qui se passe?
Modèle
Mental
@aloyer
@aloyer
@aloyer

7. Qu'est ce qui se passe?
Modèle
Mental
Ce qui est expliqué
Ce qui
n'est pas
retranscrit Modèle
Mental
@aloyer
@aloyer
@aloyer

8. Qu'est ce qui se passe?
Modèle
Mental
Ce qui est expliqué
Ce qui
n'est pas
retranscrit Modèle
Mental
Ce que l'autre comprend
@aloyer
@aloyer
@aloyer

9. Qu'est ce qui se passe?
Ce qui est
spécifié
@aloyer
@aloyer
@aloyer

10. Qu'est ce qui se passe?
Ce qui va
être testé
@aloyer
@aloyer
@aloyer
@aloyer

11. Qu'est ce qui se passe?
Ce qui va
être testé
Ce qui est
réalisé
@aloyer
@aloyer
@aloyer
@aloyer

12. Qu'est ce qui se passe?
@aloyer
@aloyer
@aloyer

13. Qu'est ce qui se passe?
@aloyer
@aloyer
@aloyer

14. Qu'est ce qui se passe?
Correspond à l'idée initiale
Ce qui a été réalisé
@aloyer
@aloyer

15. Qu'est ce qui se passe?
Correspond à l'idée
initiale
Ce qui a été réalisé
NNNAaannnnnn
vs
@aloyer
@aloyer

16. "is this a bug or is this not a bug”
a bug?
a feature?
an enhancement?
a beature?
@aloyer

17. @aloyer

18. @aloyer

19. @aloyer

20. 3 steps
3 model
3 interpretations
@aloyer

21. 3 visions
1 model
1 goal
@aloyer

22. Three Amigos @aloyer

23. http://paintings-art-picture.com/paintings/archives/85/marvel-comics-retro-captain-america-comic-panel-fighting-phase-1-so-far-so-good-aged
BDD is writing software that matters
@aloyer

24. @aloyer
@aloyer

25. BDD is about conversation
@aloyer
@aloyer

26. @aloyer

27. @aloyer

28. Why?
Goal?
Business Value?
Intention What?
How!
@aloyer
@aloyer

29. Why?
Goal?
Business Value?
In order to <achieve the vision>
Feature: ...
As a <stakeholder>
I want <value>
Intention
As a <role>
I want <goal>
So that <value>
User focused
What?
How!
@aloyer
@aloyer

30. No Narrative
No Business Value
Unnecessary Feature !
@aloyer

31. 22
http://devjam.com/2010/08/05/dudes-law-gordon-pask-shoveler/

32. In order to...
Feature: ...
As a...
I want to...
Scenario: ...
Given <a context>
When <an event happens>
Then <an outcome should occur>
BDD uses examples to illustrate behavior
@aloyer
@aloyer

33. Why do YOU
like should?
It encourages
debate, and
constant Questioning
of the premise of the
application you are
developing.
Dan North, March 2005
@aloyer

34. Feature: Account Holder withdraws cash from an ATM
!
In the following scenario, ATM will stands for
Automatic Teller Machine in other word a “Cash machine”.
!
In order to get money at any time, even when the bank is
closed
As an Account Holder
I want to withdraw cash from an ATM
!
Scenario: Account has sufficient funds
Given the account balance is 100€
When the Account Holder requests 20€
Then the ATM should dispense 20€
And the account balance should be 80€
And the card should be returned
@aloyer

35. Scenario: Account has insufficient funds
Given the account balance is 10€
And the card is valid
And the machine contains enough money
When the Account Holder requests 30€
Then the ATM should not dispense any money
And the ATM should say there are insufficient funds
And the account balance should still be 10€
And the card should be returned
@aloyer

36. Scenario: Account has insufficient funds
Given the account balance is 10€
And the card is valid
And the machine contains enough money
When the Account Holder requests 30€
Then the ATM should not dispense any money
And the ATM should say there are insufficient funds
And the account balance should still be 10€
And the card should be returned
FOCUS On the BEHAVIOR DESCRIBED!
@aloyer

37. @aloyer

38. Feature: Interpolate
!
In order to interpolate values
As an Trader
I want to interpolate values in a range of Market
data
Why this feature ?
@aloyer

39. Feature: Linear Interpolation
In order to fill the gaps and provide a value for any
maturity
As a trader responsible for market-making
I want to interpolate linearly values within a range of
points
And I want a flat extrapolation outside of the range
of points
Why this feature ?
@aloyer

40. Scenario: Change the negotiation price from positive to negative
=> soulte cashflow appears and premium cashflow is modified
!
Given an FUNKY_EXOTIC
And deal way is sell
And deal nature is TOMATO
And trade value date is 2012/07/01
And nominal is 100 JPY
And negotiation price is 0.20 JPY
When I validate the deal
Then there are 1 Price cashflows
And there are 0 fee cashflows
When I change the negotiation price to -0.3 JPY
And I validate the deal
Then there are 1 Price cashflows
And there are 1 fee cashflows
And the trade cashflow's payment date is 2012/07/01
And the trade cashflow's way is receive
And the trade cashflow's amount is 30 JPY
And the fee cashflow's payment date is 2012/07/01
And the fee cashflow's way is give
And the fee cashflow's amount is 60 JPY
What about this scenario
@aloyer

41. What about this scenario
d = new Deal();
d.SetWay(Sell);
d.SetNature(Tomato);
d.SetValueDate(new Date(...));
d.SetNominal(100, JPY);
d.SetNegotiationPrice(0.20, JPY);
cf = d.GetCashFlows();
AssertThat(IsEqual(...);
...
Scenario: Change the negotiation price from positive to negative
=> soulte cashflow appears and premium cashflow is modified
!
Given an FUNKY_EXOTIC
And deal way is sell
And deal nature is TOMATO
And trade value date is 2012/07/01
And nominal is 100 JPY
And negotiation price is 0.20 JPY
When I validate the deal
Then there are 1 Price cashflows
And there are 0 fee cashflows
When I change the negotiation price to -0.3 JPY
And I validate the deal
Then there are 1 Price cashflows
And there are 1 fee cashflows
And the trade cashflow's payment date is 2012/07/01
And the trade cashflow's way is receive
And the trade cashflow's amount is 30 JPY
And the fee cashflow's payment date is 2012/07/01
And the fee cashflow's way is give
And the fee cashflow's amount is 60 JPY
@aloyer

42. SCEnARIO: Fee and Price cashflows when the negotiation price is
set to a negative value
!
Given a sell for a nominal 100 JPY on FUNKY_EXOTIC TOMATO
negotiation price 0.20 JPY traded on 2012/07/01
When the middle officer validates the deal
Then the trade has one Price cashflow and no Fee cashflow
When the middle officer changes the negotiation price to -0.3 JPY
And the middle officer validates the deal
Then the trade has the following cashflows:
What about this scenario
Communicate With the Business People !!!
FlowType
Price
Fee
Way
Receive
Give
Amount
30
60
Currency
JPY
JPY
Payment Date
2012/07/01
2012/07/01
Remarks
100*abs(-0.3)
100*2*abs(-0.3)
@aloyer

43. Low Tech
Scenario
@aloyer
@aloyer

44. @aloyer
@aloyer

45. @aloyer
Domain Driven Design - Eric Evans @aloyer

46. In order to...
Feature: ...
As a...
I want to...
Scenario: ...
Given <a context>
When <an event happens>
Then <an outcome should occur>
Examples help discover things early
@aloyer
@aloyer

47. In order to...
Feature: ...
As a...
I want to...
Scenario: ...
Given <a context>
When <an event happens>
Then <an outcome should occur>
One may discover that one doesn't know
but others do!
@aloyer
@aloyer

48. WHAT About Automation !?!
The
Green
Thing
?
@aloyer

49. GLUECODE
BDDFRAMEWORK
SCENARIO
APPLICATION
"End to End"
UI
FEST, Selenium, Fluentlenium,
HtmlUnit, Watir...
@aloyer

50. GLUECODE
BDDFRAMEWORK
SCENARIO
APPLICATION
"End to End"
Services
Web, WCF, ...
@aloyer

51. GLUECODE
BDDFRAMEWORK
SCENARIO
APPLICATION
Sub-Module
runtime
@aloyer

52. GLUECODE
BDDFRAMEWORK
SCENARIO
APPLICATION
"Quasi-Unitaire"
runtime
@aloyer

53. GLUECODE
BDDFRAMEWORK
SCENARIO
APPLICATION
"Quasi-Unitaire"
runtime
Mock, Stubs...
@aloyer

54. GLUECODE
BDDFRAMEWORK
SCENARIO
APPLICATION
@aloyer

55. Scenario: Account has sufficient funds!
Given the account balance is 100€!
When the Account Holder requests 20€
Then the ATM should dispense 20€!
And the account balance should be 80€!
And the card should be returned
SCENARIO
GLUECODE
BDDFRAMEWORK
APPLICATION
@aloyer

56. Scenario: Account has sufficient funds!
Given the account balance is 100€!
When the Account Holder requests 20€
Then the ATM should dispense 20€!
And the account balance should be 80€!
And the card should be returned
SCENARIO
GLUECODE
BDDFRAMEWORK
APPLICATION
@aloyer

57. Scenario: Account has sufficient funds!
Given the account balance is 100€!
When the Account Holder requests 20€
Then the ATM should dispense 20€!
And the account balance should be 80€!
And the card should be returned
SCENARIO
@Given("^the account balance is (d+)€$")
public void defineAccountBalanceInEuro(BigDecimal
balance) {
throw new PendingException("Implements me!");
}
!
@When("^the Account Holder request (d+)€$")
public void withdrawInEuro (BigDecimal amount) {
throw new PendingException("Implements me!");
}
!
@Then("^the ATM should dispense (d+)€$")
public void assertMoneyDispensedInEuro (BigDecimal
amount) {
throw new PendingException("Implements me!");
}
!
!
!
@Then("^the account balance should be (d+)€$")
public void assertBalanceInEuro(BigDecimal amount) {
throw new PendingException("Implements me!");
}
!
GLUE CODE
APPLICATION
BDDFRAMEWORK
@aloyer

58. Scenario: Account has sufficient funds!
Given the account balance is 100€!
When the Account Holder requests 20€
Then the ATM should dispense 20€!
And the account balance should be 80€!
And the card should be returned
SCENARIO
@Given("^the account balance is (d+)€$")
public void defineAccountBalanceInEuro(BigDecimal
balance) {
account().setBalance(euro(balance));
}
!
@When("^the Account Holder request (d+)€$")
public void withdrawInEuro (BigDecimal amount) {
atm().withdraw(account(), euro(amount));
}
!
@Then("^the ATM should dispense (d+)€$")
public void assertMoneyDispensedInEuro (BigDecimal
amount) {
TransactionLog txLog = atm().transactionLog();!
Money dispensed = txLog.lastAmountDispensed();!
assertThat(dispensed).isEqualTo(euro(amount));
}!
!
@Then("^the account balance should be (d+)€$")
public void assertBalanceInEuro(BigDecimal amount) {
Money actualBalance = account().balance();!
assertThat(actualBalance).isEqualTo(euro(amount));
}
GLUE CODE
APPLICATION
BDDFRAMEWORK
@aloyer

59. And that’s all Folks…
for the Green Thing!
but remember,
you can
automate from
unit level to
end-to-end
level
@aloyer

60. THE Point
If only one thing must remain
@aloyer

61. BDD = Shared understanding
by discussing Examples
@aloyer

62. BDD = Shared understanding
by discussing Examples
Three AmiGOS
@aloyer

63. BDD = Shared understanding
by discussing Examples
Scenario
Three AmiGOS
@aloyer
@aloyer

64. Questions?
http://rozmaryn.deviantart.com/art/Hellboy-bw-52117973
@aloyer