Reading GOOS (V)

These are the links mentioned in this week's conversation about the 6th chapter:
Posts and Papers

• Encapsulation Definition in C2 Wiki
• Information Hiding Definition in C2 Wiki
• Encapsulation Is Not Information Hiding in C2 Wiki
• Tell Above, and Ask Below - Hybridizing OO and Functional Design by Michael Feathers
• The Four Elements of Simple Design by J. B. Rainsberger
• Clean Code Tip #12: Eliminate Boolean Arguments by Robert C. Martin
• Is Dependency Injection like Facebook? by Steve Freeman
• Object-Oriented Theater by Matteo Vaccari

Reading GOOS (IV)

These are the links mentioned in last week's conversation about the 5th chapter:

1. Posts and Papers
   • Responsibility Driven Design with Mock Objects by Marc Evers & Rob Westgeest
   • Responsibility Driven Design with Mock Objects (talk slides) by Marc Evers & Rob Westgeest
   • A Laboratory For Teaching Object-Oriented Thinking by Kent Beck and Ward Cunningham
   • How I Learned to Stop Worrying and Love the Mock by Arlo Belshee
   • How to design not to duplicate procedural workflows between test and implementation? GOOS Google Group
2. Talks
   • Why You Don't Get Mock Objects by Gregory Moeck

Reading GOOS (III)

These are the links mentioned in this week's conversation about the 4th chapter:

1. Posts
   • Beyond Test Driven Development by Liz Keogh
   • Walking Skeleton by Alistair Cockburn
   • Design as Knowledge Acquisition by Alistair Cockburn
   • Elephant carpaccio by Alistair Cockburn
   • Forget the walking skeleton – put it on crutches by Gojko Adzic
   • Another way to think about geeks and repetitive tasks by Jon Udell
   • Simplicators by Nat Pryce
   • Ports, Adapters and Simplicators by Nat Pryce
   • Walking Skeleton on C2 wiki
2. Talks
   • Decisions, decisions by Dan North
   • Fractal TDD: Using tests to drive system design by Steve Freeman

More links next week.

Introduction to TDD with Barcelona JUG and SCBCN

Yesterday Álvaro (@alvarobiz) and I facilitated the Fractions Arithmetic kata. It was an activity organized by the Barcelona Java Users Group and the Barcelona Software Craftsmanship Community. Thanks to Ignacio Cougil and Jonathan Vila for having the idea and making this event possible.

Since the kata was meant to be an introducction to TDD, we had first a short talk explaining a bit what TDD is about.

The talk took longer than I expected because we discussed about topics, such as, TDD, object-oriented design or refactoring. Thanks for the questions and comments, I think they lead to interesting discussions.

Then we started the kata working in pairs.

In the Fractions Arithmetic kata you have to develop the arithmetic of rational numbers but, in this occasion, we limited ourselves to just developing the addition of rational numbers. We modeled the rational numbers as value objects and the fractions had to be reduced.

Álvaro and I went from pair to pair commenting with them their approaches, helping when some pair was stuck, talking about some possible refactorings, etc.

I enjoyed the experience a lot and I hope all participants took something useful home.

We talked about some books and talks that might be interesting to learn more about TDD.

These are the links:

• TDD books.
  • Test Driven Development: By Example by Kent Beck. Read it to know first-hand the original TDD source
  • Diseño Ágil con TDD by Carlos Blé. A very interesting explanation of TDD in Spanish which has a Creative Commons license
  • Growing Object-Oriented Software Guided by Tests by Steve Freeman and Nat Pryce. A wonderful advanced TDD and OO book which illustrates the london School of TDD.
  • Test Driven, Practical TDD and Acceptance TDD for Java Developers by Lasse Koskela. A really great TDD book. Its second part is specially dedicated to apply TDD to specific Java technologies
  • Modern C++ Programming with Test-Driven Development by Jeff Langr. Another great book on TDD which, due to its more recent publication, also contains explanations and worked examples on the Transformation Priority Premise and the Mikado method.
• Refactoring books.
  • Refactoring, Improving the Design of Existing Code by Martin Fowler. A must-read.
  • Refactoring to Patterns by Joshua Kerievsky. Another great book which reconciled two worlds.
• Some more advanced talks we mentioned (and an extra one I forgot to mention):
  • Listening to Test Smells by Steve Freeman
  • Design How Your Objects Talk Through Mocking by Konstantin Kudryashov
  • Fractal TDD: Using tests to drive system design by Steve Freeman

Thanks to all for coming. We'll see each other in the next one.

Interesting Talk: "Refactoring Ruby with Monads"

I've just watched this wonderful talk by Tom Stuart;

• Refactoring Ruby with Monads

Reading GOOS (II)

These are the links mentioned in this week's conversation about the second chapter:

1. Talks
   • Boundaries by Gary Bernhardt
2. Books
   • Object Design: Roles, Responsibilities, and Collaborations by Rebecca Wirfs-Brock and Alan McKean
   • On Lisp by Paul Graham
3. Posts
   • Tell Don't Ask by Martin Fowler
   • Tell, Don't Ask in The Pragmatic bookshelf
   • Telling, Asking, and the Power of Jargon by Dave Thomas
   • Keep It DRY, Shy, and Tell the Other Guy by Dave Thomas and Andy Hunt
   • Law Of Demeter in C2 Wiki
   • The Law of Demeter Is Not A Dot Counting Exercise
   • JMock v. Mockito, but Not to the Death by J. B. Rainsberger
4. Some code smells
   • Shotgun Surgery in C2 Wiki
   • Inappropriate Intimacy in C2 Wiki
   • Refused Bequest
5. A kata
   • Kata Lonja

More links next week.

Bonus:

• Jason Gorman refactoring Feature Envy
• Jason Gorman refactoring Inappropriate Intimacy
• Jason Gorman refactoring Message Chains
• Jason Gorman refactoring Subtle Message Chains

Exercism: "Atbash Cipher in Clojure"

I solved the Atbash Cipher problem in Clojure.

This is my solution:


And this is the same but using the ->> macro inside the encode function:


For this exercise I had to learn how the padding parameter of the partition function works.

You can nitpick my solution here or see all the exercises I've done so far in this repository.

Exercism: "Allergies in Clojure"

I solved the Allergies problem in Clojure.

This is my first iteration of the solution:


And this is the second one which is tail-recursive:


This problem was very interesting. To solve it you need to find a solution for a problem called subset sum. Both iterations use backtracking to find the subset of numbers that sum to the allergies score.

I had used this backtracking algorithm once before to solve the N-Queens problem in Racket for the Introduction to Systematic Program Design 1 Coursera course.

You can nitpick my solution here or see all the exercises I've done so far in this repository.

Reading GOOS (I)

I'm reading Growing Object-Oriented Software Guided by Tests along with several friends from the Aprendices community.

In the next months I will be posting here resources to complement the book that are mentioned during our conversations about each chapter of the book.

These are the ones mentioned in this week's conversation about the preface and the first chapter:

1. Talks
   • Better is better by Steve Freeman
   • Design How Your Objects Talk Through Mocking by Konstantin Kudryashov
   • BDD con Javascript by Carlos Blé
2. Books
   • Test-Driven JavaScript Development by Christian Johansen
   • Implementation Patterns by Kent Beck
   • Specification by Example: How Successful Teams Deliver the Right Software by Gojko Adzic
3. Posts
   • Iterating and Incrementing to 'Get What You Need'
   • Visualising Test Terminology by Nat Pryce
   • Robert Martin compares GOOS outside in approach with his inside out approach debate at GOOS Google Group
   • Passive View
   • Big, Complex, and Tested? Just say “WHEN”. Software Development Using Presenter First
4. Test Pyramid
5. The Four Elements of Simple Design by J. B. Rainsberger
6. Putting an Age-Old Battle to Rest by J. B. Rainsberger

As you can see, we started talking about the book and then drifted a bit to talk about other somehow related topics.

More links next week.

Bonus: Michael Feathers and Steve Freeman on Design

Interesting Talk: "Types As Premature Optimization"

I've just watched this wonderful talk by Brian Shirai:

• Types As Premature Optimization