This document outlines an exercise for practicing refactoring code through pair programming. Developers pair up to refactor a tennis scoring program, taking turns coding on one shared computer every 7 minutes. The goals are to learn refactoring techniques, improve code design through applying principles like removing duplication and revealing intention, and perform small, tested changes to restructure the code without altering its functionality.

1. Coding Dojo
Refactoring
­Tennis Kata­
@AlinPandichi

2. Coding Dojo
Expectations?

3. Coding Dojo Mindset
● We are here to learn
● Safe place outside of work
● Need to slow down
● Focus on doing it right
● Non­competitive, collaborative, fun
environment

4. Practice session
● One laptop with a functional dev. env. is
connected to a projector
● Two developers pair program on the
laptop. The others are watching the code
changes.
● Every 7 minutes, one developer leaves
the laptop and the next one from the
room takes his place.

5. 4 rules of simple design
● Passes the tests
● No duplication
● Reveals intention
● Fewer elements

6. Code smells
“A surface indication that usually
corresponds to a deeper problem
in the system”
Quick to spot:
● bad names
● long method, does too much
● duplication
● dead code, etc.

7. Refactoring
“A technique for restructuring
an existing body of code,
altering its internal structure
without changing
its external behavior”

8. Small transformations
● Transformations preserving
behavior
● Small, less likely to go wrong
● System is fully working after each
change
● Verified by working tests
● Sequence of transformations
produce a significant restructuring

9. Tennis Refactoring Kata
https://github.com/emilybache/
Tennis­Refactoring­Kata

10. Retrospective
● What did you learn today?
● What happened as expected?
● What surprised you?
● What do you plan to use at work?

11. Thank you!