Legacy Code is Fear

www.mozaicworks.com

Me

Adi BolboacProgrammerOrganizational & TechnicalTrainer & Coach

www.mozaicworks.com

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

www.mozaicworks.com

Legacy code scenario

Reasons why to change existing code:

Fix a bug

Add a feature

Have automated tests for the system core

www.mozaicworks.com

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

...

www.mozaicworks.com

Current situation

You need to add some features to an existing old project

www.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

The time feels waaaaay to short

www.mozaicworks.com

Current situation

And you tell your manager: I cannot do it

www.mozaicworks.com

Current situation

But the manager says...

www.mozaicworks.com

Current situation

It takes double the time you said

www.mozaicworks.com

Current situation

Your company loses money.Your customer loses money.

www.mozaicworks.com

Current situation

Everyone is stressed

www.mozaicworks.com

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

www.mozaicworks.com

Better situation

Your team splits the end-to-end tests into integration tests and unit tests

www.mozaicworks.com

Better situation

Your team starts adding more unit tests around the area that needs to be modified

www.mozaicworks.com

Better situation

Every member of the team is using the refactoring skills to improve the design

www.mozaicworks.com

Better situation

Your team adds the new feature. It is fully test automated.

www.mozaicworks.com

Better situation

Your testers make the final exploratory and manual tests

www.mozaicworks.com

Better situation

The team delivers on time.

www.mozaicworks.com

Better situation

Your company wins money and respect from your customer.Your customer wins money and has trust in you.

www.mozaicworks.com

The problem: Legacy code is fear

Our unknowns are making us afraid

Automating tests minimizes the unknowns

By automating tests we can increase confidence

www.mozaicworks.com

Very nice

But how to do this?

www.mozaicworks.com

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

www.mozaicworks.com

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

www.mozaicworks.com

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

www.mozaicworks.com

Solve the legacy code fear: invest

Invest in the future business agility of your company

www.mozaicworks.com

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

www.mozaicworks.com

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

www.mozaicworks.com

Thank you!

www.mozaicworks.com

Contact Me

Working Fast and SAFE with Existing Code workshop

Product Inception

Code retreat

www.mozaicworks.com

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

http://www.mozaicworks.com

adrian.bolboaca@mozaicworks.com

@adibolb

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=WSI67yEZ

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

www.mozaicworks.com