app.rb

require 'sinatra'
require 'octokit'
require 'git'
require 'json'
require 'fileutils'
require 'sinatra/base'
require_relative 'helpers/helpers.rb'

class Kukla < Sinatra::Base
  helpers Sinatra::Kukla::Helpers

  get '/' do
    erb :index
  end

  post '/' do
    # Stuff
  end
  run!
end

config.ru

require 'rubygems'
require 'bundler'
require './app.rb'
Bundler.require

run Kukla

helpers

module Sinatra
  module Kukla
    module Helpers

    # Some functions here

    end
  end
end

kukla_spec.rb

require_relative '../../app.rb'
require 'spec_helper'

describe Kukla do
  include Rack::Test::Methods

  def app
    Kukla
  end

  it 'displays the home page' do
    get '/'
    expect(last_response.status).to eq 200
  end

  it 'accepts POST with JSON' do
    contents = File.read('webhook_data.json')
    json = JSON.parse(contents)
    post '/', json, {'CONTENT_TYPE' => 'application/json'}
    expect(last_response.status).to eq 200
  end
end