Goal

Practice while doing advent of code exercises.

• Object Calisthenics

• TDD

• refactoring

What is Object Calisthenics?

Model: Object Calisthenics

Why Object Calisthenics?

Code written in this style, should be

• easier to change

• easier to understand

• easier to test

• easier to reuse

This should cause code to be

• adaptable / agile / maintainable

What is TDD

Red: write a failing test

Green: in the quickest way possible

Refactor:

• cleanup code

• cleanup tests

Refactor ideas

• remove duplication

• Model: 4 rules of simple design

• refactor to patterns

• make the change easy (then make the easy change in red/green)

• tests as documentation

more:

• Book: Test Driven Development: By Example - Kent Beck

• Book: Refactoring - Martin Fowler

• Book: Refactoring to Patterns - Joshua Kerievsky

• Article: Does TDD really lead to good design? - Sandro Mancuso

• Video: Structure and Interpretation of Test Cases - Kevlin Henney

• • Model: tests must clearly express required functionality

  • Model: naming tests

  • Model: Grouping tests

Why TDD?

Writing code in this way, should result in

• not over-engineered code

• well-tested code

• safe-to-refactor code

Why Advent of Code?

These exercises always come in 2 parts:

1. initial assignment

2. a new twist in requirements causing the need to change

I expect to be able to experience 'easier to change' in the second step.

Process

Start an AoC assignment part 1

TDD:

• Red: write a failing test

• Green: in the quickest way possible

• Refactor:

• • Object Calisthenics compliant

  • (maybe) make the implementation broader by removing duplication

Finish part 1

Mini retro:

• How did it feel?

• What went well & should do more of?

Start part 2

TDD...

Finish part 2

Retro:

• Were my expectations correct??

• How did it feel?

• What went well & should do more of?

Expectations

• Object Calisthenics is sufficient for TDD's Refactor step. No other refactors are needed.

• The change-over from part 1 to part 2 will be seamless, not breaking the flow of coding.

https://github.com/TjenWellens/advent-of-calisthenics

Journal: Object Calisthenics + TDD + Advent of Code - day 1

Retro: Object Calisthenics + TDD + Advent of Code - day 1

Journal: Object Calisthenics + TDD + Advent of Code - day 2

Retro: Object Calisthenics + TDD + Advent of Code - day 2

Journal: Object Calisthenics + TDD + Advent of Code - day 4