1.
Moving away from
legacy code
with BDD

2.
BDD Practice Manager
Creator of Behat - Cucumber
for PHP
Software Engineer turned
Stakeholder whisperer
Konstantin
Kudryashov
@everzet

3.
This talk is about
• Solving purely technical “TCIAM” problem using
behaviour driven development practices and agile
discovery processes
• Planning a delivery strategy on the basis of change
appreciation
• Real-life experience

4.
Legacy projects

5.
How most teams see their
next project

6.
our next
project

7.
our next
project
their actual next
project

8.
Agile, TDD, BDD, etc… // TODO: refactor later

9.
Is it really that bad?

10.
If a project can afford a salary of an engineer
concerned about the project state,
then the project state is not that bad.

11.
// TODO: refactor later

12.
// TODO: refactor later

13.
// TODO: refactor later

14.
This world is full of brilliant projects that nobody
is concerned about. Sadly, it’s often because
there’s no one left to care.

15.
You deliver value
Just not as effectively as you could

16.
Great value + Awful code = Great product yesterday

17.
Great value + Awful code = Great product yesterday
Great value + Great code = Great product tomorrow

18.
Great value + Awful code = Great product yesterday
Great value + Great code = Great product tomorrow
No value + Any code = Awful product anytime

19.
Great value + Awful code = Great product yesterday
No value + Any code = Awful product anytime

20.
Great value + Awful code = Great product yesterday
Great value + Great code = Great product tomorrow

21.
// TODO: refactor laterAgile, TDD, BDD, etc…

22.
Rewrite
all the things!

23.
learning

24.
learning
trash bin
else

25.
learning • Agile
• XP
• BDD
trash bin
else

26.
learning • Agile
• XP
• BDD
trash bin
else

27.
learning • Agile
• XP
• BDD
trash bin
else

28.
Working system

29.
1 year later…

30.
nearly working system

31.
how come?

32.
learning • Agile
• XP
• BDD
trash bin
else

33.
learning • Agile
• XP
• BDD
trash bin
else

34.
legacylegacy

35.
legacylegacy

36.
shiny new
legacylegacy

37.
shiny new
£A
legacylegacy

38.
U
my
features!!!
shiny new
£A
legacylegacy

39.
shiny new
£A
U
my
features!!!
legacylegacy

40.
shiny new
£A + £B
U
my
features!!!
legacylegacy

41.
shiny new
£ U
my
features!!!
£A + £B
my
opportunities!!!
legacylegacy

42.
shiny new
£ U
my
features!!!
£10,000/m
£A + £B
my
opportunities!!!
legacylegacy

43.
shiny new
£ U
my
features!!!
£10,000/m £10,000*x
£A + £B
my
opportunities!!!
legacylegacy

44.
shiny new
£ U
my
features!!!
£A + £B
my
opportunities!!!
legacylegacy

45.
£A + £B
£ U
my
features!!!
shiny new
my
opportunities!!!
legacylegacy

46.
shiny new
£A + £B + £C
my
opportunities!!!
£ U
my
features!!!
legacylegacy

47.
my
opportunities!!!
£
shiny new
£A + £B + £C*?
my
opportunities!!!
£ U
my
features!!!
legacylegacy
my
opportunities!!!
£
my
opportunities!!!
£

48.
it does not work!
Well, not always...

49.
Why do legacy
projects suck?

50.
Cost
Time
cost of change

51.
How do we balance
the cost of change?

52.
Cost
Time
cost of ownership

53.
Cost
Time
cost of ownership

54.
Cost
Time
cost of change
cost of ownership

55.
Cost
Time
rewrite

56.
take ownership only when
you need to support change

57.
… Of change where?

58.
Innovation Predictability

59.
Innovation Predictability

60.
Innovation Predictability
Constant change,
never ideal
Rarest change,
good is good enough

61.
Questionnaire
1. Where is this product going?
2. Which features need to change?
3. How are they going to change?
4. How to support that change?

62.
“BDD Pipeline”
1. Where is this product going?
2. Which features need to change?
3. How are they going to change?
4. How to support that change?
• Impact Mapping
• Value Prioritisation
• Example (3 Amigos) Workshop
• BDD layers

63.
1. Where is this
product going?
Impact Mapping

64.
– Gojko Adzic
“Impact mapping is a strategic planning technique
that prevents organisations from getting lost
while building products and delivering projects,
by clearly communicating assumptions, helping
teams align their activities with overall business
objectives and make better roadmap decisions.”

65.
Four levels of Impact Map
1. Why? are we doing all this (rewrite)? What is the
goal we’re trying to achieve?
2. Who? will be impacted by it?
3. How? can they help us to achieve the goal?
4. What? can we do to support them?

66.
MVP

67.
Product Backlog

68.
In order to buy more products
As a customer
I need to have a product autocompletion in the search field

69.
2. Which features are
going to change?
Value Prioritisation

70.
In order to maintain my shopping history
As a site visitor
I need to be able to register on this site

71.
In order to maintain my shopping history
As a site visitor
I need to be able to register on this site
benefit
actor

72.
SELECT s.*
FROM backlog as s
ORDER BY s.role, s.benefit
LIMIT 25

73.
3. How are these features
going to change?
Example (3 Amigos) workshops

74.
Three layers of a User-Story
• Business rule(s)
• Communication
• Acceptance criteria

75.
Three layers of a User-Story
• Business rule(s)
• Communication in Examples
• Acceptance criteria

76.
In order to keep track of stock
As a store owner
I want to add items back to stock when they are returned
Feature: Returned items go back to stock

77.
Scenario: Refunded items should be returned to stock
In order to keep track of stock
As a store owner
I want to add items back to stock when they are returned
Feature: Returned items go back to stock

78.
Scenario: Replaced items should be returned to stock
Scenario: Refunded items should be returned to stock
In order to keep track of stock
As a store owner
I want to add items back to stock when they are returned
Feature: Returned items go back to stock

79.
Scenario: ...
Scenario: Replaced items should be returned to stock
Scenario: Refunded items should be returned to stock
In order to keep track of stock
As a store owner
I want to add items back to stock when they are returned
Feature: Returned items go back to stock

80.
Scenario: ...
Scenario: ...
Scenario: ...
Scenario: ...
Scenario: ...
Scenario: Replaced items should be returned to stock
Scenario: Refunded items should be returned to stock
In order to keep track of stock
As a store owner
I want to add items back to stock when they are returned
Feature: Returned items go back to stock

81.
Given a customer previously bought a black sweater from us
And we currently have three black sweaters left in stock
When customer returns the sweater for a refund
Then we should have four black sweaters in stock
Scenario: Refunded items should be returned to stock
In order to keep track of stock
As a store owner
I want to add items back to stock when they are returned
Feature: Returned items go back to stock

82.
4. How to support
that change?

83.
Scenario: Refunded items should be returned to stock
In order to keep track of stock
As a store owner
I want to add items back to stock when they are returned
Feature: Returned items go back to stock
Given a customer previously bought a black sweater costing 15$ from us
And we currently have three black sweaters left in stock
When customer returns the sweater for a refund
Then we should have four black sweaters in stock
And customer account should be debited with 15$

84.
Step#1: Identify change area

85.
Step#2: Identify old logic

86.
Step#3: Discuss old logic
1. What should this thing do
2. What if it suddenly stops doing it?
3. How would you know if it doesn't work?
4. How would you know if it does?

87.
Scenario: Replaced items should be returned to stock
Scenario: Refunded items should be returned to stock
In order to keep track of stock
As a store owner
I want to add items back to stock when they are returned
Feature: Returned items go back to stock

88.
Scenario: Cost of refunded item should be returned to customer bank account
Scenario: Cost of refunded item should be returned to customer PayPal account
Scenario: Cost of refunded item should be returned to customer via in-shop credits
Scenario: Replaced items should be returned to stock
Scenario: Refunded items should be returned to stock
In order to keep track of stock
As a store owner
I want to add items back to stock when they are returned
Feature: Returned items go back to stock

89.
@legacy
Scenario: Cost of refunded item should be returned to customer bank account
@legacy
Scenario: Cost of refunded item should be returned to customer PayPal account
@legacy
Scenario: Cost of refunded item should be returned to customer via in-shop credits
Scenario: Replaced items should be returned to stock
Scenario: Refunded items should be returned to stock
In order to keep track of stock
As a store owner
I want to add items back to stock when they are returned
Feature: Returned items go back to stock

90.
Step#4: Prepare for A change
1. Cover old behaviour in an end-to-end fashion
2. Make sure that scenarios/tests are green
3. Refactor code to make the lower testing possible
4. Convert scenarios/tests to lower level tests

91.
Step#5: Make a change
1. Automate new scenarios
2. Make scenarios green by applying BDD loops

92.
Stories
Examples
Describe
Implement
Design

93.
Working system

94.
1 year later…

95.
Same ashtrays, better system

96.
Stop dreaming of a greater code
Find a way to deliver a greater value

97.
We do that for clients
And help others to do it
http:// .com

98.
Thank you!
@everzet