Rspec render_template equivalent for Sinatra?

I'm building a Sinatra app currently that will be outputting JSON templates as part of an API. When testing with rails and the rspec-rails gem I was able to call:

response.should render_template('template-name')

However since I'm not using Rails I'm assuming this won't work. What's the alternative to use for Sinatra for testing the json output? Thanks!

Solution

There are some docs on using Rack Test with RSpec here, but this is how I set my stuff up. By wrapping the app in a module's class method it makes it a lot easier to run in the specs, then it's just a case of validating the response via last_response.body (which is the short answer to your question).

# config.ru

require 'rubygems'
require "bundler/setup"

root = File.expand_path File.dirname(__FILE__)
require File.join( root , "./app/config.rb" )

# everything was moved into a separate module/file 
# to make it easier to set up tests

map "/" do
  run HelloWorld.app
end

# app/config.rb
require 'main'

module HelloWorld
  def self.app
    Rack::Builder.app do
      # middleware setup here, cookies etc
      run App
    end
  end
end

# app/main.rb
require 'sinatra/base'

module HelloWorld
  class App < Sinatra::Base
    get "/", :provides => :json do
      {key: "value"}.to_json
    end
  end
end

# spec/spec_helper.rb

require 'rspec'
Spec_dir = File.expand_path( File.dirname __FILE__ )

require 'rack/test'

Dir[ File.join( Spec_dir, "/support/**/*.rb")].each do |f|
  require f
end

# spec/support/shared/all_routes.rb

require 'hello_world'  # <-- your sinatra app

shared_context "All routes" do
  include Rack::Test::Methods
  let(:app){
    HelloWorld.app 
  }
end

shared_examples_for "Any route" do
  subject { last_response }
  it { should be_ok }
end

# spec/hello_world_spec.rb
require 'spec_helper'

describe 'getting some JSON' do
  include_context "All pages"

  let(:expected) {
    '{"key": "value"}'
  }

  before do
    get '/', {}, {"HTTP_ACCEPT" => "application/json" }
  end
  it_should_behave_like "Any route"

  subject { last_response.body }
  it { should == expected }
end