Homework 4: BDD and TDD Cycle

In this homework you will use the Cucumber and RSpec tools to add new functionality to a SaaS app. This functionality will be designed following the principles of Behavior-Driven Design (BDD) and developed following Test-Driven Development (TDD).

You can either start from your HW 3 solution or from the repo saasbook/hw4_rottenpotatoes on GitHub. If you choose to do the latter, you should fork the repo and then clone from your own fork. Once you have created a fork, it is a new repo, and subsequent changes will not affect anyone else. You can now make edits and push them, and they will be saved to only your fork.

Adding director info to RottenPotatoes

Your new feature will be a "search for movies by director" feature. It will provide a link on each movie-details pages that, when clicked, displays a list of movies by the director on the page. To create this feature, follow the steps below.

Setup Cucumber and RSpec.

• Make sure your Gemfile contains these changes from Section 4.4 of ELLS, as well as the line

  gem 'rspec-rails'
  

  within the group :test, :development block.

• Run bundle install --without production to make sure the gems are properly installed.

• If necessary, set up the Cucumber directories (under features/) and the RSpec directories (under spec/), allowing overwrite of any existing files, by running the commands

  rails generate cucumber:install capybara
  rails generate cucumber_rails_training_wheels:install
  rails generate rspec:install
  

• Double-check that everything was installed by running the tasks

  rake spec
  

  and

  rake cucumber
  

  Since presumably you have no features or specs yet, both tasks should execute correctly and report that there are zero tests to run. Depending on your version of RSpec, it may also display a message stating that it was not able to find any '_spec.rb' files.

Create and apply a migration that adds the director field to the movies table. The director field should be a string containing the name of the movie's director. Hint: Use the add_column method of ActiveRecord::Migration to do this. Remember that once the migration is applied, you also have to run

rake db:test:prepare

to load the new post-migration schema into the test database!

Create controller and model specs.

• We've provided three Cucumber scenarios as a high level description of the happy path of "search for movies by director":

  • The first scenario tests the functionality for adding director info to an existing movie. Implementing this doesn't require creating any new views or controller actions, but it does require (1) modifying existing views, (2) creating a new step definition, and (3) possibly adding a line or two to features/support/paths.rb.
  • The second scenario tests the functionality for clicking a "Find Movies With Same Director" link on the movie-details page for a movie that has director info in the database. For this scenario, you'll have to modify the existing "Show Movie" view, and you'll have to add a route, view and controller method for "find movies with same director".
  • The third scenario handles the sad path when the current movie has no director info but we try to follow "Find Movies With Same Director" anyway.

• Going one Cucumber step at a time, use RSpec to create the appropriate controller and model specs to drive the creation of the new controller and model methods. You will need to write tests to drive the creation of

  • a RESTful route for "find similar movies" (Hint: Use the 'match' syntax for routes as suggested in "Non-Resource-Based Routes" at the end of section 3.9 of ELLS),
  • a controller method to receive the click on "Find Movies With Same Director", and grab the id (for example) of the current movie (i.e. the one we're trying to find movies similar to), and
  • a model method in the Movie model to find movies whose director matches that of the current movie.

• It's up to you to decide whether you want to handle the sad path of "no director" in the controller method or in the model method, but you must provide a test for whichever one you do. Remember to include the line

  require 'spec_helper'
  

  at the top of your _spec.rb files.

Once you have finished creating your feature, use SimpleCov to generate a report of your code coverage. To do this, first make sure that the line

gem 'simplecov'

exists in your Gemfile. Add the following code:

require 'simplecov' SimpleCov.start 'rails'

to the top of spec/spec_helper.rb and ```"features/support/env.rb``. Now when you run

rake spec

or

rake cucumber

SimpleCov will generate a report in a directory named coverage/. Since both RSpec and Cucumber are so widely used, SimpleCov can intelligently merge the results, so running the tests for Rspec will not overwrite the coverage results from SimpleCov and vice versa. See the screencast for step-by-step instructions on setting up SimpleCov.