Andrea Franz

Testing rails generators with Cucumber

In the last days I switched a lot of old projects to use Cucumber, then I started writing test for Web App Theme. Here I haven't models or controllers to test, because it's just a generator, but I found enjoyable the use of plain text features to describe the ThemeGenerator behavior:

Feature: Layout generation
  In order to create a great application
  I should be able to generate a layout with Web App Theme

  # script/generate theme
  Scenario: Generate a layout    
    Given I have a new rails app
    And I have no layouts
    And I have no stylesheets
    When I generate a theme
    Then I should have a layout named "application.html.erb"
    And I should have a stylesheet named "web_app_theme.css"
    And I should have a stylesheet named "web_app_theme_override.css"
    And I should have a stylesheet named "themes/default/style.css"

  # script/generate theme admin
  Scenario: Generate a layout with a name
    Given I have a new rails app
    And I have no layouts
    And I generate a theme with name "admin"
    Then I should have a layout named "admin.html.erb"

  # script/generate theme --theme="drastic-dark"
  Scenario: Generate a layout choosing a theme
    Given I have a new rails app
    And I have no stylesheets
    And I generate a theme choosing the "drastic-dark" theme
    Then I should have a stylesheet named "themes/drastic-dark/style.css"

  # script/generate theme --theme=bec --no_layout
  Scenario: Generate only stylesheets without layout
    Given I have a new rails app
    And I have no layouts
    And I generate a theme without layout choosing the "bec" theme
    Then I should have a stylesheet named "themes/bec/style.css"
    But I should not have any layouts

  # script/generate theme --app_name="My New Application"
  Scenario: Generate layout with application name
    Given I have a new rails app
    And I have no layouts
    And I generate a theme with application name "My New Application"
    Then the layout "application.html.erb" should have "My New Application" as page title

  # script/generate theme --type=sign
  Scenario: Generate layout for signin and signup
    Given I have a new rails app
    And I have no layouts
    And I generate a theme for signin and signup
    Then I should have a layout named "sign.html.erb"
    And I should have a layout named "sign.html.erb" with just a box

Here my steps:

Given /^I have a new rails app$/ do
  generate_rails_app
end

Given /^I have no layouts$/ do
  remove_layouts  
end

Given /^I have no stylesheets$/ do
  remove_stylesheets
end

Given /^I generate a theme$/ do
  generate_layout(:theme)  
end

Given /^I generate a theme with name "([^\"]*)"$/ do |name|
  generate_layout(:theme, name)
end

Given /^I generate a theme choosing the "([^\"]*)" theme$/ do |theme_name|
  generate_layout(:theme, :theme => theme_name)
end

Then /^I should have a layout named "([^\"]*)"$/ do |filename|
  layout_exists?(filename).should be_true  
end

Then /^I should have a stylesheet named "([^\"]*)"$/ do |filename|
  stylesheet_exists?(filename).should be_true    
end

Given /^I generate a theme without layout choosing the "([^\"]*)" theme$/ do |theme_name|
  generate_layout(:theme, :theme => theme_name, :no_layout => true )
end

Then /^I should not have any layouts$/ do
  layouts_count.should == 0
end

Given /^I generate a theme with application name "([^\"]*)"$/ do |name|
  generate_layout(:theme, :app_name => name )
end

Then /^the layout "([^\"]*)" should have "([^\"]*)" as page title$/ do |layout, title|
  layout_title(layout).should == title
end

Given /^I generate a theme for signin and signup$/ do
  generate_layout(:theme, :layout_type => :sign)
end

Then /^I should have a layout named "([^\"]*)" with just a box$/ do |layout|
  layout_with_box?(layout).should be_true
end

Basically I create a temp folder that I use as fake rails root, and there I launch the generator. After each feature I remove that folder.

And here my env.rb

$:.unshift(File.dirname(__FILE__) + "/../../rails_generators")
require "rubygems"
require "rails_generator"
require 'rails_generator/scripts/generate'
require "fileutils"
require "theme/theme_generator"

web_app_theme_root  = File.join(File.dirname(__FILE__), "/../../")
tmp_rails_app_name  = "tmp_rails_app"
tmp_rails_app_root  = File.join(web_app_theme_root, tmp_rails_app_name)

Rails::Generator::Base.append_sources(Rails::Generator::PathSource.new(:plugin, "#{web_app_theme_root}/rails_generators/"))

module GeneratorHelpers
  def generate_rails_app
    FileUtils.mkdir(File.join(@app_root))
  end    

  def remove_layouts
    FileUtils.rm_rf(File.join(@app_root, "app", "views", "layouts"))
  end

  def remove_stylesheets
    FileUtils.rm_rf(File.join(@app_root, "public", "stylesheets"))
  end

  def generate_layout(*args)
    options = !args.empty? && args.last.is_a?(Hash) ? args.pop : {}
    options.merge!({:destination => @app_root, :quiet => true})    
    Rails::Generator::Scripts::Generate.new.run(args, options)
  end

  def layouts_count
    Dir[File.join(@app_root, "app", "views", "layouts", "**", "*.erb")].size
  end

  def layout_exists?(filename)
    File.exists?(File.join(@app_root, "app", "views", "layouts", filename))
  end

  def stylesheet_exists?(relative_path)
    File.exists?(File.join(@app_root, "public", "stylesheets", relative_path)).should be_true
  end

  def layout_title(layout)
    File.open(File.join(@app_root, "app", "views", "layouts", layout), "r").read.match(/<title>([^<]*)<\/title>/)[1]
  end

  def layout_with_box?(layout)
    File.open(File.join(@app_root, "app", "views", "layouts", layout), "r").read =~ %r|<div id="box">|
  end
end

Before do
  @app_root = tmp_rails_app_root  
end

After do
  FileUtils.rm_rf(tmp_rails_app_root)
end

World(GeneratorHelpers)

#Cucumber #Development #Rails #Ruby #Testing

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