restrict checkout version header to just checkout class

lib/shopify_api/resources/checkout.rb

@@ -3,7 +3,10 @@
 module ShopifyAPI
   class Checkout < Base
     self.primary_key = :token
-    headers['X-Shopify-Checkout-Version'] = '2016-09-06'
+
+    def self.headers
+      super.merge('X-Shopify-Checkout-Version' => '2016-09-06')
+    end
 
     def complete
       post(:complete)

test/checkouts_test.rb

@@ -9,6 +9,11 @@ class CheckoutsTest < Test::Unit::TestCase
     @expected_checkout_id = JSON.parse(load_fixture('checkout'))['checkout']['token']
   end
 
+  test ".headers includes a version" do
+    assert_equal "2016-09-06", ShopifyAPI::Checkout.headers["X-Shopify-Checkout-Version"]
+    assert_nil ShopifyAPI::Base.headers["X-Shopify-Checkout-Version"]
+  end
+
   test ":create creates a checkout" do
     fake 'checkouts', method: :post, status: 201, body: load_fixture('checkout')
 

test/detailed_log_subscriber_test.rb

@@ -8,7 +8,6 @@ class LogSubscriberTest < Test::Unit::TestCase
     super
     @page = { :page => { :id => 1, :title => 'Shopify API' } }.to_json
     @ua_header = "\"User-Agent\"=>\"ShopifyAPI/#{ShopifyAPI::VERSION} ActiveResource/#{ActiveResource::VERSION::STRING} Ruby/#{RUBY_VERSION}\""
-    @ver_header = "\"X-Shopify-Checkout-Version\"=>\"2016-09-06\""
 
     ShopifyAPI::Base.clear_session
     ShopifyAPI::Base.site = "https://this-is-my-test-shop.myshopify.com/admin"
@@ -29,7 +28,7 @@ class LogSubscriberTest < Test::Unit::TestCase
     assert_equal 4, @logger.logged(:info).size
     assert_equal "GET https://this-is-my-test-shop.myshopify.com:443/admin/pages/1.json", @logger.logged(:info)[0]
     assert_match /\-\-\> 200/, @logger.logged(:info)[1]
-    assert_equal "Headers: {\"Accept\"=>\"application/json\", #{@ua_header}, #{@ver_header}}", @logger.logged(:info)[2]
+    assert_equal "Headers: {\"Accept\"=>\"application/json\", #{@ua_header}}", @logger.logged(:info)[2]
     assert_match /Response:\n\{\"page\"\:\{((\"id\"\:1)|(\"title\"\:\"Shopify API\")),((\"id\"\:1)|(\"title\"\:\"Shopify API\"))\}\}/,  @logger.logged(:info)[3]
 
   end
@@ -44,7 +43,7 @@ class LogSubscriberTest < Test::Unit::TestCase
     assert_equal 4, @logger.logged(:info).size
     assert_equal "GET https://this-is-my-test-shop.myshopify.com:443/admin/pages/2.json", @logger.logged(:info)[0]
     assert_match /\-\-\> 404/, @logger.logged(:info)[1]
-    assert_equal "Headers: {\"Accept\"=>\"application/json\", #{@ua_header}, #{@ver_header}}", @logger.logged(:info)[2]
+    assert_equal "Headers: {\"Accept\"=>\"application/json\", #{@ua_header}}", @logger.logged(:info)[2]
     assert_equal "Response:", @logger.logged(:info)[3]
   end
 end