Ecosyste.ms: Awesome

An open API service indexing awesome lists of open source software.

Awesome Lists | Featured Topics | Projects

https://github.com/sewera/product-export-refactoring-kata

Kata for practicing refactoring to Design Patterns, based on Joshua Kerievsky's book
https://github.com/sewera/product-export-refactoring-kata

design-patterns kata refactoring refactoring-to-pattern

Last synced: about 1 month ago
JSON representation

Kata for practicing refactoring to Design Patterns, based on Joshua Kerievsky's book

Awesome Lists containing this project

README 

        
# Product export refactoring kata



Check out the [resources](https://www.sewera.dev/rtp) for this kata.



The main book for this kata is [Joshua Kerievsky's "Refactoring to Patterns"](https://www.google.com/books/edition/Refactoring_to_Patterns/Oxm8R1dY3RwC).



This kata is based on Emily Bache's version:

[emilybache/Product-Export-Refactoring-Kata](https://github.com/emilybache/Product-Export-Refactoring-Kata).



## Tags



1. [t-initial-setup]

   - This is what we'd find in a legacy code

   - No tests

2. [t-tests-in-place]

   - System is under test

3. [t-test-for-different-tax-calculation]

   - Code coverage tool uncovered a different tax calculation algorithm

4. [t-first-test-refactoring]

   - Test code should also be refactored

5. [t-add-lombok-dependency]

   - We are Java developers of the modern age

   - Some people will call it poor man's Kotlin. And they'd be right

6. [t-classes-lombokified-and-simplified]

   - Look at this removed code, oh my, the [removed code](https://github.com/sewera/product-export-refactoring-kata/compare/t-first-test-refactoring...t-classes-lombokified-and-simplified)!

7. [t-tax-calculator-under-test]

   - Tax calculation is tricky and expensive to break

   - We have to make sure we didn't break anything

8. [t-ledger-introduced]

   - We finally got our domain expert

   - How would you call something that holds a list of orders?

9. [t-ledger-renamed-to-account]

   - After further discussions,

     our domain expert says that it should be an Account.

10. [t-tax-calculator-removed]

    - But tax calculation is hard, we don't want to lose it!

    - Don't worry, now the Account is responsible for it

11. [t-rtp-price-implicit-leaf-extracted]

    - Alright, _finally_ we can do the refactoring to a Composite pattern

    - Look at [one of the commits](https://github.com/sewera/product-export-refactoring-kata/commit/57809d0383f7ee0b4184ded14e138f73bedf95c5)

      - It's very small

      - There are a lot of such commits, so Pair Programming may be necessary

12. [t-strategy-pattern-in-product]

    - [Introduction](https://github.com/sewera/product-export-refactoring-kata/commit/11b9948368649ef1df9644aa50c13779b2e48737)

    - [Implementation in StoreEvent](https://github.com/sewera/product-export-refactoring-kata/commit/802b2148a7863c4b4fea237007c80e9d0a4d41b1#diff-2743d87c473294f182a077056669ad94c433d76ba30b63452dcc32f27d6eef23R33-R41)

    - That strategy pattern came out of nowhere!

      - But it solved a problem of duplication at that time

      - It turned out not to be useful later, so it was removed

13. [t-rtp-refactoring-to-composite-done]

    - What a journey that was

    - The design is better, the tests pass after each commit,

      so we could continuously deliver it to production

    - Better, shorter functions

    - But still not declarative enough

14. [t-domain-objects-moved-to-domain-package]

    - Wait, why are there xml representations of domain objects

      in the objects themselves?

    - You can argue that it _is_ the domain of the project,

      because the project is solely for exporting XML

15. [t-rtp-xml-builder-implemented]

    - Luckily, we've got some spare time,

      so we'll make the design _even better_

      by implementing the Builder pattern

16. [t-rtp-encapsulated-composite-with-builder-in-price]

    - Now the design better reflects the intent

    - It's more declarative instead of imperative

17. [t-rtp-simplify-price-after-encapsulation-with-builder]

    - Further simplification

18. [t-rtp-simplify-serialization-in-xml-exporter]

    - Further deduplication

19. [t-refactored]

    - That's much better

    - Thankfully we did it in Pair Programming,

      because a [PR for it](https://github.com/sewera/product-export-refactoring-kata/compare/t-initial-setup...t-refactored) would be huge!



[t-initial-setup]: https://github.com/sewera/product-export-refactoring-kata/tree/t-initial-setup

[t-tests-in-place]: https://github.com/sewera/product-export-refactoring-kata/tree/t-tests-in-place

[t-test-for-different-tax-calculation]: https://github.com/sewera/product-export-refactoring-kata/tree/t-test-for-different-tax-calculation

[t-first-test-refactoring]: https://github.com/sewera/product-export-refactoring-kata/tree/t-first-test-refactoring

[t-add-lombok-dependency]: https://github.com/sewera/product-export-refactoring-kata/tree/t-add-lombok-dependency

[t-classes-lombokified-and-simplified]: https://github.com/sewera/product-export-refactoring-kata/tree/t-classes-lombokified-and-simplified

[t-tax-calculator-under-test]: https://github.com/sewera/product-export-refactoring-kata/tree/t-tax-calculator-under-test

[t-ledger-introduced]: https://github.com/sewera/product-export-refactoring-kata/tree/t-ledger-introduced

[t-ledger-renamed-to-account]: https://github.com/sewera/product-export-refactoring-kata/tree/t-ledger-renamed-to-account

[t-tax-calculator-removed]: https://github.com/sewera/product-export-refactoring-kata/tree/t-tax-calculator-removed

[t-rtp-price-implicit-leaf-extracted]: https://github.com/sewera/product-export-refactoring-kata/tree/t-rtp-price-implicit-leaf-extracted

[t-strategy-pattern-in-product]: https://github.com/sewera/product-export-refactoring-kata/tree/t-strategy-pattern-in-product

[t-rtp-refactoring-to-composite-done]: https://github.com/sewera/product-export-refactoring-kata/tree/t-rtp-refactoring-to-composite-done

[t-domain-objects-moved-to-domain-package]: https://github.com/sewera/product-export-refactoring-kata/tree/t-domain-objects-moved-to-domain-package

[t-rtp-xml-builder-implemented]: https://github.com/sewera/product-export-refactoring-kata/tree/t-rtp-xml-builder-implemented

[t-rtp-encapsulated-composite-with-builder-in-price]: https://github.com/sewera/product-export-refactoring-kata/tree/t-rtp-encapsulated-composite-with-builder-in-price

[t-rtp-simplify-price-after-encapsulation-with-builder]: https://github.com/sewera/product-export-refactoring-kata/tree/t-rtp-simplify-price-after-encapsulation-with-builder

[t-rtp-simplify-serialization-in-xml-exporter]: https://github.com/sewera/product-export-refactoring-kata/tree/t-rtp-simplify-serialization-in-xml-exporter

[t-refactored]: https://github.com/sewera/product-export-refactoring-kata/tree/t-refactored