Arne is a developer, public speaker, programming coach, author and open-source contributor. With a passion for both human and programming languages, he has spent the last decade teaching and exploring the finer points of Ruby, LISP, Haskell, Mandarin Chinese, and others. When not hopping conferences or Pacific islands, he can be found at his home base in Berlin, brewing fine teas while pondering the future of open-source and the web.

Arne's articles

  1. Customizing Trello with Ruby

    Trello is a great collaboration tool. It’s based around boards, which contain lists of cards. How you use it is up to you, as it’s one of those simple tools with many uses. Want to plan or coordinate with multiple people, or just manage your own todos? Just set up a board and get going.

    All of Trello’s features can be controlled through its API, and it’s completely free, including use of the web and mobile apps, as well as access to the API. With the ruby-trello gem you can be automating your boards in no time.

  2. Mutation Testing with Mutant

    As Rubyists we are no strangers to testing. Unit testing is not just best practice, it is dogma. Code is considered broken until we have tests to prove otherwise. But not all test suites are created equal. Writing good tests is an art, and bad tests can be worse than no tests, slowing development down without increasing the confidence we have in our code.

    So who tests the tests? The question may seem frivolous, but the answer is simple, Mutant does!

    Mutant is a mutation tester. To appreciate what it does, let’s imagine doing its job by hand. Appoint a person in your team to be the saboteur, their job is to pick a piece of fully tested code and deliberately introduce defects. If this can be done without raising an alarm, in other words, without causing a test to fail, then a test is missing. It’s then up to the original author to add a test case to detect the sabotage.

  3. Ruby’s Pathname API

    Pathname docs

    Ruby’s standard library is a treasure trove of useful classes, and the Pathname class is certainly one of them. Introduced in Ruby 1.9, Pathname represents a path on the file system, providing convenient access to functionality that is otherwise scattered across a handful of other classes like File, FileTest, and Dir.

    Now that the life of Ruby 1.8 has officially come to an end, and 1.9 is nearing its fifth birthday, it’s high time to drop the legacy support and embrace the elegance and ease of use Pathname has to offer.