CodeCampIasi25Oct2014

1. Legacy Code is Fear
www.mozaicworks.com

2. Me
Adi Bolboacă
Programmer
Organizational & Technical
Trainer & Coach www.mozaicworks.com

3. Legacy code scenario
Current situation vs Better situation
Not knowing what the actual code does
Vs
Gradually understanding the code and
changing it to the minimum
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4. Legacy code scenario
Reasons why to change existing code:
Fix a bug
Add a feature
Have automated tests for the system core
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5. Legacy code scenario
Reasons why not to change existing
code:
It looks ugly
I would like to see nicer code
I want to update to newest framework
...
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6. Current situation
You need to add some features
to an existing old project www.mozaicworks.com

7. Current situation
They tell you that you have a very
short time to do it www.mozaicworks.com

8. Current situation
You are afraid to change the
system www.mozaicworks.com

9. Current situation
The time feels waaaaay to short
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10. Current situation
And you tell your manager: I
cannot do it
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11. Current situation
But the manager says...
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12. Current situation
It takes double the time you said
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13. Current situation
Your company loses money.
Your customer loses money. www.mozaicworks.com

14. Current situation
Everyone is stressed
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15. Better situation
Someone signs a contract to add
some features to an existing old
project www.mozaicworks.com

16. Better situation
Your team starts writing
characterization tests to
understand the change www.mozaicworks.com

17. Better situation
Your team writes end-to-end
tests to understand the external
dependencies
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18. Better situation
Your team splits the end-to-end
tests into integration tests and
unit tests
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19. Better situation
Your team starts adding more unit
tests around the area that needs
to be modified
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20. Better situation
Every member of the team is using
the refactoring skills to improve
the design
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21. Better situation
Your team adds the new feature.
It is fully test automated.
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22. Better situation
Your testers make the final
exploratory and manual tests
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23. Better situation
The team delivers on time.
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24. Better situation
Your company wins money and
respect from your customer.
Your customer wins money and has
trust in you.
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25. The problem: Legacy code is fear
Our unknowns are making us afraid
Automating tests minimizes the unknowns
By automating tests we can increase
confidence
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26. Very nice
But how to do this?
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27. Find the known unknowns of the
team
Talk with the team
Find what they do not know: domain
knowledge, programming languages, unit
testing, acceptance testing, frameworks,
etc
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28. Make small scale experiments
Use a smaller problem at first
Learn how to write charaterization tests
for that problem
Use coding dojos and mob programming
to practice together
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29. The littany against fear
I must not fear.
Fear is the mind-killer.
Fear is the little-death that brings total obliteration.
I will face my fear.
I will permit it to pass over me and through me.
And when it has gone past I will turn the inner eye to
see its path.
Where the fear has gone there will be nothing.... only I
will remain
Dune by Frank Herbert
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30. Solve the legacy code fear: invest
Invest in the future business agility of your
company
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31. Solve the legacy code fear: learn
Find the unknowns of the team
Make a medium-term learning program
Make small scale experiments
Learn
Extend to bigger scale experiments
Learn
Do a small change request in production
Learn
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32. What's next?
Read the Working Effectively with Legacy
code book by Michael Feathers
Find a good trainer to help the team learn
Build learning program with team&trainer
Learn from each experience
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33. Questions?
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34. Thank you!
Working Fast and SAFE with Existing Product Inception
Code retreat
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See the slides at
http://www.slideshare.net/adibolb

35. Extend your mentoring & training
capacity
Accelerate learning through
communities of practice
Grow your functional leaders and top
talents
http://www.mozaicworks.com
adrian.bolboaca@mozaicworks.com
@adibolb

36. References
http://upload.wikimedia.org/wikipedia/commons/7/7f/Snake_warning_sign.jpg
http://upload.wikimedia.org/wikipedia/commons/4/44/CatLolCatExample.jpg
http://upload.wikimedia.org/wikipedia/commons/8/88/I_IZ_SERIUS_ADMNIM_THIZ_IZ_SERIUS_BIZNIS_lolcat.jpg
http://pixabay.com/p-160097/?no_redirect
http://www.damemagazine.com/sites/default/files/styles/feature_wide/public/field/image/biological-clock.jpg?itok=http://fc01.deviantart.net/fs71/i/2012/149/6/9/no__9gag__by_hujikari-d51hu4l.jpg
http://upload.wikimedia.org/wikipedia/commons/1/12/We_Can_Do_It!.jpg
http://upload.wikimedia.org/wikipedia/commons/2/25/Dive_hand_signal_Descend.png
http://pixabay.com/go/?t=/static/uploads/photo/2012/04/18/13/01/sign-36968_150.png%3Fattachment
http://pixabay.com/static/uploads/photo/2014/06/03/19/38/plate-361516_640.jpg
http://upload.wikimedia.org/wikipedia/commons/0/0c/Dive_hand_signal_OK_1.png
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