You can easily use tools such as Behat and phpspec for practicing BDD in PHP. Regardless of the specific BDD tools, the question of how to do BDD “properly” arises. According to Dan North, initiator of the BDD philosophy, it should be be practiced as a “mutliple-stakeholder, agile methodology”. However, most open-source projects are not developed with an explicit agile methodology. Also, there are hardly any stakeholder roles that are clearly distinguishable from each other - often contributor and user are actually one and the same. So, in the case of open-source projects, you can question the benefit of BDD.

1. BDD in open-source projects
Is it really beneficial?
FABIAN KISS

2. I AM
Fabian Kiss
@head_revision
headrevision
Passionate Behat user, contributor, and blogger

3. I WORK AT

4. WE ARE HERE
www.ymc.ch
@ymc_ch

5. I WILL
Question BDD!

6. I WILL
Question BDD!
Dan North: « BDD is a [...] multiple-stakeholder, agile methodology »

7. I WILL
Question BDD!
Dan North: « BDD is a [...] multiple-stakeholder, agile methodology »
BDD is beneficial in agile customer projects.

8. I WILL
Question BDD!
Dan North: « BDD is a [...] multiple-stakeholder, agile methodology »
BDD is beneficial in agile customer projects.
customer pays
→ explicit customer
→ agile process

9. I WILL
Question BDD!
Dan North: « BDD is a [...] multiple-stakeholder, agile methodology »
BDD is beneficial in agile customer projects.
open-source projects
customer pays
→ explicit customer
→ agile process
developers work for free
→ no explicit customer
→ emergent process

10. I WILL
Question BDD!
Dan North: « BDD is a [...] multiple-stakeholder, agile methodology »
BDD is beneficial in agile customer projects.
customer pays
→ explicit customer
→ agile process
Is it beneficial in open-source projects as well?
developers work for free
→ no explicit customer
→ emergent process

12. PRIME EXAMPLE

13. PRIME EXAMPLE
USES
BOTH TOOLS

15. BDD IS NOT ABOUT
TOOLS

16. BDD IS NOT ABOUT
TOOLS
BDD IS ABOUT
METHODOLOGY

17. TOOL

18. METHOD
TOOL
SpecBDD
StoryBDD

19. METHOD
SYNTAX
TOOL
SpecBDD
Code, Functions/Methods as
specifications
StoryBDD

20. METHOD
SYNTAX
TOOL
SpecBDD
function it_greets_with_hello_world()
{
$this->greet()->shouldReturn(
'Hello World'
);
}
StoryBDD

21. METHOD
SYNTAX
TOOL
SpecBDD
function it_greets_with_hello_world()
{
$this->greet()->shouldReturn(
'Hello World'
);
}
StoryBDD
Plain text, one or more scenarios
for (fictitious) user story,
described as prose in givenwhen-then scheme (Gherkin
syntax)

22. METHOD
SYNTAX
TOOL
SpecBDD
function it_greets_with_hello_world()
{
$this->greet()->shouldReturn(
'Hello World'
);
}
StoryBDD
Scenario:
Given a
When an
Then an
A successful scenario
precondition
event occurred
outcome is achieved

23. METHOD
SpecBDD
NOTION
Dan North 2003:
SYNTAX
function it_greets_with_hello_world()
{
$this->greet()->shouldReturn(
'Hello World'
);
}
StoryBDD
TOOL
names of test methods
describe intended behavior
Scenario:
Given a
When an
Then an
A successful scenario
precondition
event occurred
outcome is achieved

24. METHOD
NOTION
SYNTAX
TOOL
SpecBDD
StoryBDD
“TDD done right”
function it_greets_with_hello_world()
{
$this->greet()->shouldReturn(
'Hello World'
);
}
Scenario:
Given a
When an
Then an
A successful scenario
precondition
event occurred
outcome is achieved

25. QUESTION #1
Should you use SpecBDD as substitute for xUnit?

26. QUESTION #1
Should you use SpecBDD as substitute for xUnit?
phpspec
PHPUnit

27. QUESTION #1
Should you use SpecBDD as substitute for xUnit?
phpspec
CUSTOMER
PROJECT
no problem in principal
PHPUnit

28. QUESTION #1
Should you use SpecBDD as substitute for xUnit?
phpspec
CUSTOMER
PROJECT
OPEN-SOURCE
PROJECT
PHPUnit
no problem in principal
community developers unfamiliar with the code might be irritated

29. QUESTION #1
Should you use SpecBDD as substitute for xUnit?
phpspec
CUSTOMER
PROJECT
OPEN-SOURCE
PROJECT
PHPUnit
no problem in principal
community developers unfamiliar with the code might be irritated
“Where are the unit tests?”
“How to unit test with that?”

30. QUESTION #1
Should you use SpecBDD as substitute for xUnit?
phpspec
CUSTOMER
PROJECT
OPEN-SOURCE
PROJECT
PHPUnit
no problem in principal
community developers unfamiliar with the code might be irritated
“Where are the unit tests?”
“How to unit test with that?”

31. METHOD
NOTION
SYNTAX
TOOL
SpecBDD
StoryBDD
?
“TDD done right”
function it_greets_with_hello_world()
{
$this->greet()->shouldReturn(
'Hello World'
);
}
Scenario:
Given a
When an
Then an
A successful scenario
precondition
event occurred
outcome is achieved

32. METHOD
SpecBDD
StoryBDD
Dan North 2011:
NOTION
SYNTAX
TOOL
“TDD done right”
function it_greets_with_hello_world()
{
$this->greet()->shouldReturn(
'Hello World'
);
}
« BDD is about understanding
the customer's need [...] (and
being able to prove that with
an evolving suite of
acceptance tests) »
Scenario:
Given a
When an
Then an
A successful scenario
precondition
event occurred
outcome is achieved

33. METHOD
NOTION
SYNTAX
TOOL
SpecBDD
“TDD done right”
function it_greets_with_hello_world()
{
$this->greet()->shouldReturn(
'Hello World'
);
}
StoryBDD
understanding
customer’s need
+ evolving suite of
acceptance tests
Scenario:
Given a
When an
Then an
A successful scenario
precondition
event occurred
outcome is achieved

34. STORYBDD IN DETAIL

35. STORYBDD IN DETAIL
implementing something correctly && implementing the right thing

36. STORYBDD IN DETAIL
implementing something correctly && implementing the right thing
acceptance tests are secondary to the understanding

37. STORYBDD IN DETAIL
implementing something correctly && implementing the right thing
acceptance tests are secondary to the understanding
customer explicitly asks for their production && co-produces them

38. STORYBDD IN DETAIL
implementing something correctly && implementing the right thing
acceptance tests are secondary to the understanding
customer explicitly asks for their production && co-produces them

39. QUESTION #2
Who decides what the right thing is?

40. QUESTION #2
Who decides what the right thing is?
CUSTOMER
PROJECT
customer, thus no problem

41. QUESTION #2
Who decides what the right thing is?
CUSTOMER
PROJECT
OPEN-SOURCE
PROJECT
customer, thus no problem
developer, thus potential problem

42. QUESTION #2
Who decides what the right thing is?
CUSTOMER
PROJECT
OPEN-SOURCE
PROJECT
customer, thus no problem
developer, thus potential problem
customer === (other) developers (i.e. bundle level) → no problem
elsewise (i.e. application level) → “language of the customer” is not met

43. QUESTION #2
Who decides what the right thing is?
CUSTOMER
PROJECT
OPEN-SOURCE
PROJECT
customer, thus no problem
developer, thus potential problem
customer === (other) developers (i.e. bundle level) → no problem
elsewise (i.e. application level) → “language of the customer” is not met

44. STORYBDD IN DETAIL
implementing something correctly && implementing the right thing
acceptance tests are secondary to the understanding
customer explicitly asks for their production && co-produces them

45. QUESTION #3
How to facilitate understanding?

46. QUESTION #3
How to facilitate understanding?
CUSTOMER
PROJECT
face-to-face communication, thus no problem

47. QUESTION #3
How to facilitate understanding?
CUSTOMER
PROJECT
OPEN-SOURCE
PROJECT
face-to-face communication, thus no problem
communication mainly via issue tracker. pull requests, Twitter, etc.
→ StoryBDD is impeded

48. QUESTION #3
How to facilitate understanding?
CUSTOMER
PROJECT
OPEN-SOURCE
PROJECT
face-to-face communication, thus no problem
communication mainly via issue tracker. pull requests, Twitter, etc.
→ StoryBDD is impeded
→ but StoryBDD is the solution

49. QUESTION #3
How to facilitate understanding?
CUSTOMER
PROJECT
OPEN-SOURCE
PROJECT
face-to-face communication, thus no problem
communication mainly via issue tracker. pull requests, Twitter, etc.
→ StoryBDD is impeded
→ but StoryBDD is the solution
(watching the execution of the Behat suite live in a browser facilitates
your understanding about the features of the open-source project)

50. QUESTION #3
How to facilitate understanding?
CUSTOMER
PROJECT
OPEN-SOURCE
PROJECT
face-to-face communication, thus no problem
communication mainly via issue tracker. pull requests, Twitter, etc.
→ StoryBDD is impeded
→ but StoryBDD is the solution
(but browser is emulated so far)
(watching the execution of the Behat suite live in a browser facilitates
your understanding about the features of the open-source project)

51. STORYBDD IN DETAIL
implementing something correctly && implementing the right thing
acceptance tests are secondary to the understanding
customer explicitly asks for their production && co-produces them

52. QUESTION #4
Who asks for their production?

53. QUESTION #4
Who asks for their production?
CUSTOMER
PROJECT
customer, thus no problem

54. QUESTION #4
Who asks for their production?
CUSTOMER
PROJECT
OPEN-SOURCE
PROJECT
customer, thus no problem
(some) community developers, thus potential problem

55. QUESTION #4
Who asks for their production?
CUSTOMER
PROJECT
OPEN-SOURCE
PROJECT
customer, thus no problem
(some) community developers, thus potential problem
StoryBDD might be process overhead → more impediment than benefit

56. QUESTION #4
Who asks for their production?
CUSTOMER
PROJECT
OPEN-SOURCE
PROJECT
customer, thus no problem
(some) community developers, thus potential problem
StoryBDD might be process overhead → more impediment than benefit
“The code doesn’t get green anymore!”
“If the worst comes to the worst, who decides to abandon Behat?”

57. QUESTION #4
Who asks for their production?
CUSTOMER
PROJECT
OPEN-SOURCE
PROJECT
customer, thus no problem
(some) community developers, thus potential problem
StoryBDD might be process overhead → more impediment than benefit
“The code doesn’t get green anymore!” (at early development stage)
“If the worst comes to the worst, who decides to abandon Behat?”

58. CONCLUSION

59. CONCLUSION

60. CONCLUSION
SpecBDD might benefit open-source projects.

61. CONCLUSION
SpecBDD might benefit open-source projects.
StoryBDD might benefit open-source projects.

62. CONCLUSION
SpecBDD might benefit open-source projects.
StoryBDD might benefit open-source projects.
(even more than customer projects)

63. CONCLUSION
SpecBDD might benefit open-source projects.
StoryBDD might benefit open-source projects.
(even more than customer projects)
StoryBDD might impede open-source projects.

64. CONCLUSION
SpecBDD might benefit open-source projects.
StoryBDD might benefit open-source projects.
(even more than customer projects)
StoryBDD might impede open-source projects.
What to do?

65. CONCLUSION
SpecBDD might benefit open-source projects.
StoryBDD might benefit open-source projects.
(even more than customer projects)
StoryBDD might impede open-source projects.
What to do?
Contribute!

66. CONCLUSION
SpecBDD might benefit open-source projects.
StoryBDD might benefit open-source projects.
(even more than customer projects)
StoryBDD might impede open-source projects.
What to do?
Contribute!
e.g.

67. QUESTIONS?
fabian.kiss@ymc.ch
@head_revision
www.ymc.ch
Quotes:
Slide 06: How to sell BDD to the business by Dan North
Slide 32: Defining BDD by Dan North
Photo Credits:
Slide 01: off to save something by bokeh burger
Slide 04: Alpkäse, Aeschi bei Spiez by Time.Captured
Slide 12: Background image by Sylius
Slide 15: Swiss Army by Jim Pennucci
Slide 58: Vancouver Symphony Orchestra with Bramwell Tovey by Vancouver 125