legacy code is fear @codecamp iasi 25 10 2014
TRANSCRIPT
Me
Adi BolboacăProgrammer
Organizational & TechnicalTrainer & Coach www.mozaicworks.com
Legacy code scenario
Current situation vs Better situation
Not knowing what the actual code doesVs
Gradually understanding the code and changing it to the minimum
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Legacy code scenario
Reasons why to change existing code:
Fix a bugAdd a feature
Have automated tests for the system core
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Legacy code scenario
Reasons why not to change existing code:
It looks uglyI would like to see nicer code
I want to update to newest framework...
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Current situation
You need to add some features to an existing old projectwww.mozaicworks.com
Current situation
They tell you that you have a very short time to do it www.mozaicworks.com
Current situation
You are afraid to change the system www.mozaicworks.com
Current situation
And you tell your manager: I cannot do it
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Current situation
Your company loses money.Your customer loses money.
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Better situation
Someone signs a contract to add some features to an existing old
project www.mozaicworks.com
Better situation
Your team starts writing characterization tests to understand the change www.mozaicworks.com
Better situation
Your team writes end-to-end tests to understand the external
dependencies
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Better situation
Your team splits the end-to-end tests into integration tests and
unit tests
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Better situation
Your team starts adding more unit tests around the area that needs
to be modified
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Better situation
Every member of the team is using the refactoring skills to improve
the design
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Better situation
Your team adds the new feature. It is fully test automated.
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Better situation
Your testers make the final exploratory and manual tests
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Better situation
Your company wins money and respect from your customer.
Your customer wins money and has trust in you.
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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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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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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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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 Herbertwww.mozaicworks.com
Solve the legacy code fear: invest
Invest in the future business agility of your company
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Solve the legacy code fear: learn
Find the unknowns of the teamMake a medium-term learning program
Make small scale experimentsLearn
Extend to bigger scale experimentsLearn
Do a small change request in productionLearn
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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 experiencewww.mozaicworks.com
Thank you!
Working Fast and SAFE with Existing Code workshop
Product Inception
Code retreat
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See the slides at http://www.slideshare.net/adibolb
Extend your mentoring & training capacityAccelerate learning through communities of practiceGrow your functional leaders and top talents
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@adibolb
References
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