Sinatra + RSpec basic testing

sinatra_app.rb

require 'json'
require 'sequel'
require 'sinatra/base'

class SinatraApp < Sinatra::Base
  # https://stackoverflow.com/a/20726197/6243352
  def initialize(app = nil, db)
    super(app)
    @db = db
  end

  #configure do
  #  DB = Sequel.sqlite
  #  DB.create_table :notes do
  #    primary_key :id
  #    String :content
  #  end
  #end

  get '/api/notes/:id' do
    note = @db[:notes].first(:id => params[:id])
    if note.nil?
      404
    else
      note.to_json
    end
  end

  post '/api/notes' do
    body = JSON.parse(request.body.read)
    if !body.has_key? "content"
      422
    elsif @db[:notes].insert(:content => body["content"]).nil?
      500
    else
      200
    end
  end
end

sinatra_app_spec.rb

require 'json'
require 'rack/test'
require 'sinatra_app'

def parse_json?(json)
  JSON.parse(json)
rescue JSON::ParserError => e
  nil
end

describe 'Sinatra App' do
  include Rack::Test::Methods

  let(:db) {Sequel.sqlite}
  let(:app) {SinatraApp.new(db)}

  before do
    db.create_table :notes do
      primary_key :id
      String :content
    end
  end
  after do
    db.drop_table :notes
  end
 
  it 'works on POST and GET /api/notes/' do 
    post '/api/notes', {:content => 'hello world'}.to_json
    expect(last_response.ok?).to be true
    expect(last_response.status).to eq 200

    get '/api/notes/1'
    body = parse_json?(last_response.body)
    expect(body).to be_instance_of Hash
    expect(body).to eq({'id' => 1, 'content' => 'hello world'})
  end
end