Bank account kata

Think of your personal bank account experience When in doubt, go for the simplest solution

Requirements

• Deposit and Withdrawal
• Transfer
• Account statement (date, amount, balance)
• Statement printing
• Statement filters (just deposits, withdrawal, date)

The Rules

1. One level of indentation per method
2. Don’t use the ELSE keyword
3. Wrap all primitives and Strings
4. First class collections
5. One dot per line
6. Don’t abbreviate
7. Keep all entities small (50 lines)
8. No classes with more than two instance variables
9. No getters/setters/properties

For more information:

• Object Calisthenics pdf
• Object Calisthenics (full book), Jeff Bay in: The ThoughtWorks Anthology. Pragmatic Bookshelf 2008
• Original idea for the kata: How Object-Oriented Are You Feeling Today? - Krzysztof Jelski (Session on the Software Craftsmanship UK 2011 conference)