Riotjs: A JavaScript Unit Testing Framework

I really like Riot, the Ruby unit testing framework, so I decided to port it to JavaScript. You can get it from GitHub at alexyoung/riotjs.

I’ve worked hard to keep the syntax minimal. This is challenging in JavaScript, as you may have gathered from my Fear and Loathing in JavaScript DSLs article.

There’s actually no need for a JavaScript “DSL” in this case — riotjs could work fine by passing around objects. It’s just that riot tests are so terse that I wanted to carry this over to JavaScript. Up until now I’ve been using unittest.js from script.aculo.us and I always felt the tests were too messy.

Here’s a few interesting things to note about it:

• Like cucumber the output is verbose
• It’ll work with Rhino, I do a lot of work this way because it’s very fast and focused
• I colourize the output in the terminal
• Your tests will also run in a browser without any modification
• There are some aliases: should is aliased to asserts, and given is aliased as context
• Those methods are not global because I’m a cunning magician

Here’s an example test:

load('test_helper.js');

Riot.context('Functions', function() {

  given('a function to curry', function() {
    var add  = function(a, b) { return a + b; },
        add1 = Closure.curry(add, 1);
    should('return expected values', add1(10)).equals(11);
  });

  given('a function to memoize', function() {
    var fibo = Closure.memoize([0, 1], function(recur, n) {
      return recur(n - 1) + recur(n - 2);
    });
    should('return fibonacci numbers', fibo(10)).equals(55);
  });
});

Riot.run();

This test is from my closure library, which is a bunch of functional stuff (with lazy evaluation!) for JavaScript. Here’s what the output looks like:

I could also include that script in HTML, because Riot.run will automatically run the tests onload. Additionally, Riot.run can be passed a function containing the tests, rather than having a call to run. The reason I call run here is because I have a set of files I want to run to test the entire libraries.

Don’t be afraid to message me about riotjs on GitHub, it’s a work in progress so I’d appreciate contributions and thoughts.