Step By Step: Setting Up minitest and Cucumber with Rails

I’ve tried a couple times in the past to successfully set up a Rails application with both minitest and Cucumber; each time, I ran in to issues. I’m not entirely sure why I ran into the issues I did, but I just couldn’t seem to get things working. Recently, I managed to get everything going with almost no effort. Here’s what I did.

Step 1: Creating and Configuring a New Rails App with minitest

For the sake of simplicity, we’ll assume that we’re creating a new Rails application. To do so, we’ll want to skip the standard usage of Test::Unit

rails new <app_name> --skip-test-unit

Immediately after this, we’ll need to install and initialize the minitest-rails gem

group :test, :development do
  ...
  gem 'minitest-rails', '~> 0.3.0` # as of this writing
  ...
end

bundle install and then initialize the gem in the app.

rails g mini_test:install

The last thing we’ll do is make sure our generators behave accordingly. To do that, add the following logic to the config/application.rb config block:

config.generators do |g|
  g.test_framework :mini_test, :spec => true, :fixture => false
end

This turns on minitest’s spec functionality and turns off fixture generation. If you don’t want to use minispec or if you do want to use fixtures, just alter the values accordingly.

Step 2: Setting up Cucumber

Okay, at this point we have our foundational test suite set up. Now we need to add cucumber to the mix.

Add cucumber-rails to your Gemfile as you normally would.

group :test do
  gem 'cucumber-rails', "~> 1.3.0"
  gem "database_cleaner", "~> 0.9.1"
end

Call bundle install and then call the cucumber Rails generator:

rails g cucumber:install

Now, add the following lines of code to features/support/env.rb. (I placed mine near the top.)

require 'minitest/spec'
World(MiniTest::Assertions)
MiniTest::Spec.new(nil)

For greater separation, the previous lines of code above can be added to a different support file.

Step 3: Running the Tests

At this point, everything should work. Let’s find out with a couple simple tests.

minispec Test

Create the following test file and model:

require_relative "../minitest_helper"

describe Foo do
  it "must be valid" do
    Foo.must_respond_to :new
  end
end

And the corresponding model file:

class Foo
end

Notice in the first line of foo_test.rb that we’re using require_relative instead of a normal require call. We do this to avoid the need to use rake. Now, rather than running bundle exec rake minitest:models and running all the models, we can execute bundle exec ruby test/models/foo_test.rb.

Cucumber Test

Create the following Cucumber “feature” file:

Feature: test
  In order to test cucumber
  a user
  wants to successfully land on the home page

  Scenario: foo
    Given I am on the home page
     Then I should see "Ruby on Rails: Welcome aboard"

And an associated step file:

Given /^I am on the home page$/ do
  visit "/"
end

Then /^I should see \"([^"]+)"$/ do |string|
  page.has_content?(string).must_equal true
end

Run the test and everything should be green.

bundle exec cucumber features/test.feature

Final Thoughts

I like minitest a lot, mainly because it’s fast, it’s simple, and it’s included in Ruby 1.9+, but there are drawbacks; the two main ones for me are its readability and the lack of integration with the vim-rails plugin. Neither of these “drawbacks” are deal breakers, however: the vim-rails plugin will eventually support it, and there are gems to make the suite more “civilized” (listed below).

So if you like the idea of a really simple and fast test suite, and you don’t mind the syntax, give minitest a go on your next project. Oh, and let me know how it works out for you.

Further Reading