snippet.rb

require 'rubygems'
require 'spec'
require 'spec/interop/test'
# require 'test/spec'
require 'sinatra/base'
require 'rack/test'

class Dummy < Sinatra::Base 
  
  set :public, 'public'
  set :views, 'views'
  
  get '/' do
    "hello world"
  end
  
end

class Test::Unit::TestCase
  include Rack::Test::Methods
  
  def app
    Dummy.new
  end
  
  ### NB!!! ############
  # Commenting / Uncommenting this method will show the error
  # 
  # def setup
  #   Sinatra::Base.set :environment, :test
  # end
  
end

describe "Dummy" do 
  
  it "should return hello world from the / (this works in both cases)" do
    get '/'
    assert_equal('hello world', last_response.body)
  end
  
  it "should NOT return a Sinatra::ShowExceptions object" do
    assert_no_match(/Sinatra::ShowExceptions/, app.inspect )
  end
  
  it "should be a Dummy class" do
    assert_equal(Dummy, app.class )
  end
  
end #/ Dummy