Credits

Inspired by J. B. Rainsberger

You can practice different things using this code base. For example…

Golden Master

We can’t write reasonable unit tests without refactorings first. But we don’t want to refactor without tests at all.

But we can test the application as a whole. Gain control over all external input sources (RNGs, system time, keyboard input and so on). Then save all outputs produced (console output, emails sent, files changed etc). This is our Golden Master.

Now we can change the code and compare if it still yields the same results as before.

Free Fall

This is another thing to try out. And probably it’s a good idea to not learn this in production. Just use your IDE refactorings. Do not waste time to understand the code. Trust your IDE and use features like extract method or invert if statement. You will be surprised about the results.

Get the Code

On GitHub (This kata can be done using C#, C++, C, Clojure, COBOL, CoffeeScript, D, F#, Go, Groovy, Java, JavaScript, Kotlin, Lua, Objective C, Perl, PHP, PowerShell, Python, Racket, Ruby, Rust, Scala, ShellScript, Smalltalk, Swift, TypeScript, VB6) If your favorite language is missing, feel free to create a pull request. Be sure the maintainer will be happy ;-)

Image credits

Image by Rachel M. Carmena. It represents a greeting of respect and gratitude made at the beginning and at the end of a kata.