Fix constant duplication (#159)

.gitignore

@@ -9,4 +9,5 @@
 /tmp/
 *.swp
 vendor/bundle
-/.idea
+/.idea
+.ruby-version

lib/chartmogul/csv/line_items/one_time.rb

@@ -3,9 +3,9 @@
 module ChartMogul
   module CSV
     module LineItems
-      ONE_TIME_HEADERS = %w[Invoice\ external\ ID External\ ID Subscription\ external\ ID Subscription\ set\ external\ ID Type Amount\ in\ cents Plan Service\ period\ start Service\ period\ end Quantity Proration Discount\ code Discount\ amount Tax\ amount Description Transaction\ fee Account\ Code Transaction\ fees\ currency Discount\ description Balance\ transfer].freeze
-
       class OneTime < Base
+        HEADERS = %w[Invoice\ external\ ID External\ ID Subscription\ external\ ID Subscription\ set\ external\ ID Type Amount\ in\ cents Plan Service\ period\ start Service\ period\ end Quantity Proration Discount\ code Discount\ amount Tax\ amount Description Transaction\ fee Account\ Code Transaction\ fees\ currency Discount\ description Balance\ transfer].freeze
+
         writeable_attr :invoice_external_id
         writeable_attr :external_id
         writeable_attr :subscription_external_id
@@ -32,7 +32,7 @@ def type
         end
 
         def self.headers
-          ChartMogul::CSV::LineItems::ONE_TIME_HEADERS
+          HEADERS
         end
       end
     end

lib/chartmogul/csv/line_items/subscription.rb

@@ -3,10 +3,10 @@
 module ChartMogul
   module CSV
     module LineItems
-      # from https://chartmogul-samples.s3-eu-west-1.amazonaws.com/public/04_Invoice_line_items.csv
-      SUBSCRIPTION_HEADERS = %w[Invoice\ external\ ID External\ ID Subscription\ external\ ID Subscription\ set\ external\ ID Type Amount\ in\ cents Plan Service\ period\ start Service\ period\ end Quantity Proration Discount\ code Discount\ amount Tax\ amount Description Transaction\ fee Account\ Code Transaction\ fees\ currency Discount\ description Proration\ type Event\ Order].freeze
-
       class Subscription < Base
+        # from https://chartmogul-samples.s3-eu-west-1.amazonaws.com/public/04_Invoice_line_items.csv
+        HEADERS = %w[Invoice\ external\ ID External\ ID Subscription\ external\ ID Subscription\ set\ external\ ID Type Amount\ in\ cents Plan Service\ period\ start Service\ period\ end Quantity Proration Discount\ code Discount\ amount Tax\ amount Description Transaction\ fee Account\ Code Transaction\ fees\ currency Discount\ description Proration\ type Event\ Order].freeze
+
         writeable_attr :invoice_external_id
         writeable_attr :external_id
         writeable_attr :subscription_external_id
@@ -34,7 +34,7 @@ def type
         end
 
         def self.headers
-          ChartMogul::CSV::LineItems::SUBSCRIPTION_HEADERS
+          HEADERS
         end
       end
     end

lib/chartmogul/csv/line_items/trial.rb

@@ -3,10 +3,6 @@
 module ChartMogul
   module CSV
     module LineItems
-      # from https://chartmogul-samples.s3-eu-west-1.amazonaws.com/public/04_Invoice_line_items.csv
-      SUBSCRIPTION_HEADERS = ['Invoice external ID', 'External ID', 'Subscription external ID',
-                              'Subscription set external ID', 'Type', 'Amount in cents', 'Plan', 'Service period start', 'Service period end', 'Quantity', 'Proration', 'Discount code', 'Discount amount', 'Tax amount', 'Description', 'Transaction fee', 'Account Code', 'Transaction fees currency', 'Discount description', 'Proration type', 'Event Order'].freeze
-
       class Trial < Subscription
         writeable_attr :invoice_external_id
         writeable_attr :external_id
@@ -35,7 +31,7 @@ def type
         end
 
         def self.headers
-          ChartMogul::CSV::LineItems::SUBSCRIPTION_HEADERS
+          HEADERS
         end
       end
     end