• AugustMeetingTwoThousandTen

Simpler Test-driven Web Development with Sinatra and MongoDB

The potent combination of an extremely flexible and forgiving (migration-free!) database like MongoDB and an extremely lightweight web app framework like Sinatra allows you to do test-driven development much more simply than with Ruby on Rails / MySQL or lightweight web frameworks in other languages.

We will be using Rack::Test for more "acceptance"-style testing and Test::Unit for traditional unit testing, which will be very comfortable for programmers already familiar with XUnit-style testing. Come create a complete, working web app in record time test-first using Sinatra and MongoDB.

Topics covered:

• Ruby
• Sinatra
• MongoDB
• Mongo_Mapper
• Test::Unit
• Rack::Test
• Markup Validity

Preparation: Any laptop with Ruby (ideally 1.9+) installed will do...

• gem install sinatra
• gem install mongo_mapper
• gem install rack-test
• gem install markup_validity

• download the appropriate MongoDB binary

• extract MongoDB package somewhere convenient
• create a /data/db directory on the same drive/mount where you extracted it

As a teaser, here's an illustration of our simple first test

   1 # hello_test.rb
   2 
   3   require 'rubygems'
   4   require 'rack/test'
   5   require 'test/unit'
   6   require 'hello'     # <-This specifies the SUT
   7 
   8   class MyAppTest < Test::Unit::TestCase
   9     include Rack::Test::Methods
  10 
  11     def app
  12       Sinatra::Application
  13     end
  14 
  15     def test_my_default
  16       get '/'
  17       assert_equal 'Hello World!', last_response.body
  18     end
  19   end

And the second, which causes a slight refactor of the first test

   1   require 'markup_validity'
   2 .
   3 .
   4 .
   5    def test_my_default
   6       get '/'
   7       assert(last_response.body.include?('Hello World!'), "No 'Hello World!' in '#{last_response.body}'")
   8    end
   9 
  10    def test_body_is_html
  11       get '/'
  12       assert_xhtml_transitional(last_response.body)
  13    end
  14 .
  15 .
  16 .

Eventually, we'll be asserting against the HTML output, like:

   1   require 'nokogiri'
   2 .
   3 .
   4 .
   5    def test_input_field_named_greetee
   6       get '/'
   7       doc = Nokogiri::HTML(last_response.body)
   8       assert_equal('greetee', doc.xpath('//form/input/@name'))
   9    end
  10 .
  11 .
  12 .

The "Requirements" of the project are:

• Web application
• Use a database (shared with other apps)
• Enter 1 person at a time to greet
• Greetings page greets all people in database

• Consistent HTML look for all pages, use image.