Code Katas

Mars Rover built entirely with AI using NestJS and hexagonal architecture. Deploy, move and rotate covered with unit and e2e tests. Comparative write-up against the manual version still pending.

Mock-101 workshop: where and how to use test doubles without coupling to implementation details.

Wrap text at N columns. A perfect drill for thinking edge cases before typing.

Ranking with ties and custom sorting. Small yet very expressive for domain modeling.

Rover on a grid with commands and obstacles. Outside-in iteration starting from the acceptance test.

Same kata in Kotlin, solved outside-in. The inside-out version remains as a pending challenge.

Minimal-viable password validation: length, uppercase, lowercase, digit and underscore. A short kata ideal for practicing red-green-refactor TDD with an incremental checklist.

Roy Osherove's classic solved step by step with red-green-refactor TDD: custom delimiters, multi-line, negative-number exception, and filtering of numbers > 1000.

Transform integers to Roman numerals up to 3000, with an exception past the maximum. Strict TDD plus mutation testing with pitest to measure test quality.

Seven solutions to the same problem: from plain if/else to a Specification pattern with predicates. A lab to compare styles and see how the design shifts.