no need to boot a whole dummy Rails app in testing

We only test a single controller in isolation and we can get away with
just initializing a dummy Rails.application object and declaring routes.

This gets rid of the runtime dependency to "rails" in the gemspec, which
in the long run is bad practice for plugins to declare anyway.

Author: mislav

api-pagination.gemspec

@@ -16,8 +16,7 @@ Gem::Specification.new do |s|
   s.test_files    = Dir['spec/**/*']
   s.require_paths = ['lib']
 
-  s.add_dependency 'rails', '>= 3.0.0'
-
-  s.add_development_dependency 'bundler', '~> 1.3'
+  s.add_development_dependency 'actionpack'
+  s.add_development_dependency 'activemodel'
   s.add_development_dependency 'rspec-rails'
 end

spec/controllers/numbers_controller_spec.rb

@@ -1,6 +1,35 @@
 require 'spec_helper'
 
-describe NumbersController do
+Rails.application.routes.draw do
+  resources :numbers, only: [:index]
+end
+
+# quacks like Kaminari
+PaginatedSet = Struct.new(:current_page, :total_count) do
+  def limit_value() 25 end
+
+  def total_pages
+    total_count.zero? ? 1 : (total_count.to_f / limit_value).ceil
+  end
+
+  def first_page?() current_page == 1 end
+  def last_page?() current_page == total_pages end
+end
+
+class NumbersController < ActionController::Base
+  include Rails.application.routes.url_helpers
+
+  after_filter only: [:index] { paginate(:numbers) }
+
+  def index
+    page = params.fetch(:page, 1).to_i
+    total = params.fetch(:count).to_i
+    @numbers = PaginatedSet.new(page, total)
+    render json: @numbers
+  end
+end
+
+describe NumbersController, :type => :controller do
   describe 'GET #index' do
     context 'without enough items to give more than one page' do
       it 'should not paginate' do