Jul 31 2007

Rails fast test suite

Rails convention suggests Model classes that traditionally extend ActiveRecord::Base with the corresponding unit tests depending on the database. I prefer to separate the business from the data access layers by having a few ActiveRecord children handling persistence (not unlike repositories) with the bulk of the application logic residing in classes that are unaware of the database.

I find it useful to add a separate test suite for handling the tests for those classes by creating a new directory, e.g. test/fastunit and a Rake test task (lib/tasks/fastunit.rake) that runs the tests in it.

namespace :test do
  Rake::TestTask.new('fastunit') do |t|
    t.pattern = 'test/fastunit/*_test.rb'


Adding test:fastunit to the prerequisites of the main test task ensures the suite will be ran as part of the full test build.

One of the advantages to this approach is the instant feedback of running rake test:fastunit - these tests are inherently faster. I run these tests often whilst developing to ensure things are going smoothly and only run the full build before checkins.

This technique renders the built-in test:units task slightly ambiguous as ActiveRecord tests are now presented more like functional tests, which is not entirely incorrect, because they do, after all, hit the database.