spec_helper and Gemfile from a Padrino app. This successfully runs RSpec/Capybara Unit/Feature tests.

Gemfile

source 'https://rubygems.org'

# Padrino supports Ruby version 1.9 and later
ruby '2.3.0'

# Project requirements
gem 'rake'

# Component requirements
gem 'bcrypt'
gem 'sass'
gem 'haml'
gem 'activerecord', '>= 3.1', :require => 'active_record'
gem 'sqlite3'

# Test requirements
group :test do
  gem 'shoulda'
  gem 'rack-test', :require => 'rack/test'
  gem 'rspec-padrino'
  gem 'capybara'
end

# Padrino Stable Gem
gem 'padrino', '0.13.1'

spec_helper.rb

RACK_ENV = 'test' unless defined?(RACK_ENV)
require File.expand_path(File.dirname(__FILE__) + "/../config/boot")
Dir[File.expand_path(File.dirname(__FILE__) + "/../app/helpers/**/*.rb")].each(&method(:require))
require 'rack/test'
require 'rspec/padrino'
require 'capybara/rspec'

Capybara.app = Padrino.application

RSpec.configure do |config|
  config.include Rack::Test::Methods
  config.include RSpec::Padrino
  config.include Capybara::DSL

  config.expect_with :rspec do |expectations|
    expectations.include_chain_clauses_in_custom_matcher_descriptions = true
  end

  config.mock_with :rspec do |mocks|
    mocks.verify_partial_doubles = true
  end
end