Faster Unit Testing in Rails Without Loading Rails

faster-unit-testing-in-rails-without-rails.rb

# Running a single minimalistic unit test with Rails 4 and Ruby 2.1.1 is a lot faster
# if you avoid loading Rails:

# Running the test *with* Rails

time ruby -Itest test/models/my_model_test.rb # => real ~ 6s

# Running the test *without* Rails

time ruby -Itest/no_rails test/models/my_model_test.rb # => real ~ 0.6s

# app/models/my_model.rb (your application logic that doesn't depend on Rails)

class MyModel
  def self.foobar
    "foobar"
  end
end

# test/no_rails/test_helper.rb

require 'bundler/setup'
require 'minitest/unit'
require 'minitest/autorun'

# test/models/my_model_test.rb

require 'test_helper'
require File.expand_path('../../../app/models/my_model', __FILE__)
class MyModelTest < MiniTest::Unit::TestCase
  def test_foobar
    assert_equal "foobar", MyModel.foobar
  end
end