Testing your Rails plugin

Rida Al Barazi

When I first released both ArabicHelper and SimplySearchable I didn’t have any tests for them because I didn’t know the right way to write those tests. After doing some digging and looking at other plugins tests I found out how, and I’m sharing that here with you.

Specifically for ActiveRecord extensions you need a database and models definition to test your plugin, to do that you have to:

• Require ActiveRecord gem:

  require 'activerecord'
  

• Establish an ActiveRecord connection to a memory based sqlite3 database:

  ActiveRecord::Base.establish_connection(:adapter => "sqlite3", :dbfile => ":memory:")
  

• Define both setup_db and teardown_db:

  def setup_db
    ActiveRecord::Schema.define(:version => 1) do
      create_table :posts do |t|
        t.column :title, :string
        t.column :body, :text
        t.column :category_id, :integer
      end
      create_table :categories do |t|
        t.column :id, :integer
        t.column :name, :string
      end
    end
  end
  
  def teardown_db
    ActiveRecord::Base.connection.tables.each do |table|
      ActiveRecord::Base.connection.drop_table(table)
    end
  end
  

• Define your models:

  class Post < ActiveRecord::Base
    belongs_to :category
  end
  class Category < ActiveRecord::Base
    has_many :posts
  end
  

• Finally define both setup and teardown methods in your test class (Note that all the above should be placed before your test class definition):

    def setup
      setup_db
    end
  
    def teardown
      teardown_db
    end
  

That’s it, now you can write your tests as if you’re writing them in your Rails application unit tests. Check the following for more example tests:

• SimplySearchable test
• acts_as_tree test
• acts_as_versioned test

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