Fix Rails 3 doesn't have #none method

find_with_order.gemspec

@@ -29,9 +29,9 @@ Gem::Specification.new do |spec|
 
   spec.add_development_dependency "bundler", "~> 1.11"
   spec.add_development_dependency "rake", "~> 12.0"
-  spec.add_development_dependency "mysql2", "~> 0.3.21"
   spec.add_development_dependency "minitest", "~> 5.0"
 
   spec.add_dependency "rails", ">= 3"
+  spec.add_dependency "mysql2", ">= 0.3"
 
 end

gemfiles/3.2.gemfile

@@ -5,6 +5,7 @@ source 'https://rubygems.org'
 gem "activerecord", "~> 3.2"
 
 group :test do
+  gem 'mysql2' , '0.3.21'
   gem "simplecov"
   gem "codeclimate-test-reporter", "~> 1.0.0"
 end

gemfiles/4.2.gemfile

@@ -5,6 +5,7 @@ source 'https://rubygems.org'
 gem "activerecord", "~> 4.2"
 
 group :test do
+  gem 'mysql2' , '0.3.21'
   gem "simplecov"
   gem "codeclimate-test-reporter", "~> 1.0.0"
 end

gemfiles/5.0.gemfile

@@ -5,6 +5,7 @@ source 'https://rubygems.org'
 gem "activerecord", "~> 5.0"
 
 group :test do
+  gem 'mysql2' , '0.3.21'
   gem "simplecov"
   gem "codeclimate-test-reporter", "~> 1.0.0"
 end

lib/find_with_order.rb

@@ -8,3 +8,10 @@ def find_with_order(ids)
     where(id: ids).order("field(id, #{ids.join(',')})")
   end
 end
+unless ActiveRecord::Base.respond_to?(:none) # extend only if not implement yet
+  class ActiveRecord::Base
+    def self.none #For Rails 3
+      where('1=0')
+    end
+  end
+end

test/find_with_order_test.rb

@@ -8,10 +8,25 @@ def test_that_it_has_a_version_number
     refute_nil ::FindWithOrder::VERSION
   end
 
-  def test_basic_find_with_order
-    order = [2, 1, 3]
-    order_map = order.each_with_index.to_h
-    expected = User.where(:id => order).to_a.sort_by{|user| order_map[user.id] }
-    assert_equal expected, User.find_with_order(order)
+  def test_find_id_with_order
+    test_order = proc{|order|
+      expected = User.where(:id => order).to_a.sort_by{|user| order.index(user.id) }
+      assert_equal expected, User.find_with_order(order)
+    }
+    test_order.call [1, 2, 3]
+    test_order.call [1, 3, 2]
+    test_order.call [2, 1, 3]
+    test_order.call [2, 3, 1]
+    test_order.call [3, 1, 2]
+    test_order.call [3, 2, 1]
+  end
+
+  def test_none
+    assert_equal [], User.none.find_with_order([1, 2, 3]).to_a
+  end
+
+  def test_find_empty
+    expected = []
+    assert_equal expected, User.find_with_order([])
   end
 end