Rails plugins and libraries / Testing plugins

From WhyNotWiki

[edit] test_helper files / Test initialization

[edit] Example from acts_as_ordered_tree

Notable features:

• Depends on parent app's Rails "environment" (boot.rb) but provides own database and schema. (Bad: Means it can only be tested when installed as plugin within context of an app.)
• Uses sqlite3 (in memory), so:
  • it doesn't affect the parent app's test database (so that doesn't have to be reloaded when the plugin test is finished),
  • the user of the plugin doesn't need to do any extra configuration to run tests,
  • and it doesn't even litter the filesystem with any database files!

./vendor/plugins/acts_as_ordered_tree/test/abstract_unit.rb

ENV["RAILS_ENV"] = "test"

require File.dirname(__FILE__) + '/../../../../config/boot'

require 'rubygems'
require 'test/unit'
# The only part of Rails that is actually needed, apparently
require 'active_record'

# Use a special database for this plugin tests. Output to a local log file.
config = YAML::load(IO.read(File.dirname(__FILE__) + '/database.yml'))
ActiveRecord::Base.logger = Logger.new(File.dirname(__FILE__) + '/debug.log')
ActiveRecord::Base.establish_connection(config['database'])

# Load the plugin itself
require File.dirname(__FILE__) + '/../init'

# An ActiveRecord model 
require File.dirname(__FILE__) + '/../lib/person'

# Basically equivalent to a migration. Creates the schema/tables.
load(File.dirname(__FILE__) + '/schema.rb')

vendor/plugins/acts_as_ordered_tree/test/database.yml

database:
  adapter: sqlite3
  database: ":memory:"

vendor/plugins/acts_as_ordered_tree/test/schema.rb

ActiveRecord::Schema.define(:version => 1) do
  create_table "people", :force => true do |t|
    t.column "parent_id" ,:integer ,:null => false ,:default => 0
    t.column "position"  ,:integer
    t.column "name"      ,:string
  end
  add_index "people", ["parent_id"], :name => "index_people_on_parent_id"
end

vendor/plugins/acts_as_ordered_tree/lib/person.rb

class Person < ActiveRecord::Base
  acts_as_ordered_tree
end