Kata: Roman Numerals in Clojure (2nd time)

I've just redone the Roman Numerals kata in Clojure following the advices about test-driving algorithms that Sandro Mancuso gave during his Crafted Code course:

• Grow an algorithm bit by bit
• Delay treating exceptions (in this case, because they are more complex)
• Intentionally cause duplication
• Focus on simple structures first

The resulting code to convert decimals up to 3999 to roman numerals is much simpler than the code I got the first time I did the kata.

I think the reason is that the first time I started refactoring too soon and that hid the duplication pattern that would have lead me to this simpler solution.

As in the previous version, I extended the kata to also convert decimal numbers over 3999.

This is the resulting code:

and these are the tests using Midje:

To document the TDD process I commited the code after every passing test and every refactor. You can find the commits step by step here.

This time it was a bit easier to derive the algorithm only using strict TDD.

You can find all the code in this repository in GitHub.