Rails' `assigns` helper for Sinatra tests by lifo

gistfile1.rbx

$: << "/Users/lifo/Rails/sinatra/lib"
require 'rubygems'
require 'sinatra'
require 'sinatra/test/unit'
require 'app'

class Rack::Response
  attr_accessor :variables
end

class Rack::MockResponse
  attr_accessor :variables
  
  def initialize_with_variables(status, headers, body, errors=StringIO.new(""))
    self.variables = body.variables if body.respond_to?(:variables=)
    initialize_without_variables(status, headers, body, errors)
  end
  alias_method :initialize_without_variables, :initialize
  alias_method :initialize, :initialize_with_variables

  def assigns(name)
    variables["@#{name}"]
  end
end

class Sinatra::EventContext
  def finish
    result = super
    self.response.variables = {}
    instance_variables.each do |var|
      self.response.variables[var] = instance_variable_get(var)
    end
    result
  end
end

class AppTest < Test::Unit::TestCase
  def test_my_default
    get_it '/'
    assert_equal 'Hello Templates', @response.body
    assert_equal 1, @response.assigns(:hello)
  end
end

Sinatra::EventContext does not exist in latest versions, so this example is outdated.