Ciklum Java Meetup in Gdansk 14.03.2016

1. Ciklum Java Meet Up: Testing in Legacy:
From Rags to Riches

2. {
“First name”: “Taras”,
“Last name”: “Slipets”,
“E-mail”: “taras.slipets@gmail.com”,
“LinkedIn Profile”: “http://www.linkedin.com/
pub/taras-slipets/
48/466/516”,
“Interests”: [
“Software Engineering”,
“Music”,
“Skiing”,
]
}
2
About me

3. 3
About presentation
• System that we’ve
received for
improvement
• General feeling about
legacy
• Effective steps that
were performed
• What we’ve eventually
reached

4. Just long-term project
4
Legacy system is…

5. Where do we go now
• General feeling about legacy
• System that we’ve received for improvement
• Effective steps that were performed
• What we’ve eventually reached
5

6. What we’ve received
6
• No documentation
• No developers who has worked on it
• Impatient customers
11-years old system SUCCESSFULLY running on production servers
• Written in Java 1.4
• No frameworks usage
• Patient management & other surprises…

7. 7
Bus factor*
*# of team members that need to be hit by a bus to
kill a project

8. 8
What we’d like to have?
Shiny system with all
cutting-edge frameworks
Reduce pain of
maintenance and support

9. Where do we go now
• General feeling about legacy
• System that we’ve received for
improvement
• Effective steps that were performed
• What we’ve eventually reached
9

10. So, how we did it?
10

11. Setup your environment
11
DEV QA STAGE PROD

12. 12
WRITE DOCS

13. Logs,
logs,
logs
13

14. 14
Domain
model –
classes
level

15. Domain
model –
database
level
15

16. 16
Domain
model –
workflows

17. Peer (“DUCK”) review VERY often
17

18. Before changing code
18

19. WE NEED TO ENSURE IT WORKS!
19

20. 20
Testing

21. Testing levels
Unit tests
21
Integration tests
System and
UI tests

22. Test existing and expected behavior
22EXPECTATION REALITY

23. System/UI testing (feature testing)
23
System
tests
Application
Under
testing
Process Process

24. External world communication
24

25. 25
Tests automation

26. Unit
Tests
Integration/
Acceptance Tests
System
Tests
Tests automation
26
Unit
Tests
Manual
Tests

27. 27
Finally –
let’s touch
THE
code!

28. Top occurring issues
28
“do-stuff”
methods
I’m aware
of everything”
classes
“Celebrities”
classes/
interfaces
“Magic goes
here” blocks
without comments
Just
obsolete
code

29. WHAT TO DO?
29
KEEP
CALM
AND
DIVIDE ET
IMPERA

30. How about
30

31. 31
Refactoring
facilities
• Extract method
• Extract interface
• Parameter object
• Method object
• Replace type-
checking code with
State/Strategy
• Move method/field
• …

32. 32
Unit tests
jumps into

33. Frameworks
33

34. 34
After initial tests are
written,
use PowerMock
as indicator
of bad
system design

35. 35

36. 36
No, Thanks!
We are too busy!

37. 37
Most used in our case
• Template method
• Strategy
• State
• Visitor
• Command
• Chain of Responsibility
• Observer

38. And
again
–
logs,
logs,
logs
38

39. 39
Hey, where are new features?

40. Extend functionality AFA it’s possible
40

41. How deep refactoring should be?
41

42. • S.O.L.I.D.
• D.R.Y.
• K.I.S.S.
• …
42
Theory the Godmother

43. In real world
43
KEEP IT TIME-BOXED!

44. Building
&deployment
44
Operational
Monitoring

45. Logging
45

46. 46
Operations are happy

47. Where do we go now
• General feeling about legacy
• System that we’ve received for
improvement
• Effective steps that were performed
• What we’ve eventually reached
47

48. 48
Dreams come true - build-pipeline!
Auto Auto Auto Manual
Code
Done
Unit
Tests
Integrate Acceptance
test
Deploy to
production
Continuous Delivery

49. 49
The winner takes it all

50. 50
A-team!

51. 51
• Old project is not a
disaster, but challenge
• Start from environment
setup and feature
testing. At least to some
extent
• Share knowledge with
your colleagues and
write docs
• Do not underestimate
power of classical
remedies (patterns,
working techniques)
• Be agile ;)
Lessons learned

52. THANK YOU!