Carbon offset support (#201)

- New carbon_offset.rb class
- Ability to pass `with_carbon_offset` parameter when creating, buying or re-rating a shipment

.rubocop.yml

@@ -3,3 +3,7 @@ inherit_from: easycop.yml
 # We are ignoring RSpec/FilePath because Simplecov doesn't play nice with nested spec files
 RSpec/FilePath:
   Enabled: false
+# TODO: Remove this once we start using keyword arguments
+Style/OptionalBooleanParameter:
+  Exclude:
+    - 'lib/easypost/shipment.rb'

lib/easypost.rb

@@ -16,6 +16,7 @@
 require 'easypost/batch'
 require 'easypost/billing'
 require 'easypost/brand'
+require 'easypost/carbon_offset'
 require 'easypost/carrier_account'
 require 'easypost/carrier_type'
 require 'easypost/customs_info'

lib/easypost/carbon_offset.rb

@@ -0,0 +1,5 @@
+# frozen_string_literal: true
+
+# The CarbonOffset object is a summary of carbon offset data for a given rate, including grams, price and currency
+class EasyPost::CarbonOffset < EasyPost::Resource
+end

lib/easypost/shipment.rb

@@ -5,8 +5,22 @@
 # The workhorse of the EasyPost API, a Shipment is made up of a "to" and "from" Address, the Parcel
 # being shipped, and any customs forms required for international deliveries.
 class EasyPost::Shipment < EasyPost::Resource
+  # Create a Shipment.
+  def self.create(params = {}, api_key = nil, with_carbon_offset = false)
+    wrapped_params = {
+      shipment: params,
+      carbon_offset: with_carbon_offset,
+    }
+
+    response = EasyPost.make_request(:post, url, api_key, wrapped_params)
+    EasyPost::Util.convert_to_easypost_object(response, api_key)
+  end
+
   # Regenerate the rates of a Shipment.
-  def regenerate_rates(params = {})
+  def regenerate_rates(with_carbon_offset = false)
+    params = {}
+    params[:carbon_offset] = with_carbon_offset
+
     response = EasyPost.make_request(:post, "#{url}/rerate", @api_key, params)
     refresh_from(response, @api_key)
 
@@ -21,13 +35,15 @@ def get_smartrates # rubocop:disable Naming/AccessorMethodName
   end
 
   # Buy a Shipment.
-  def buy(params = {})
+  def buy(params = {}, with_carbon_offset = false)
     if params.instance_of?(EasyPost::Rate)
       temp = params.clone
       params = {}
       params[:rate] = temp
     end
 
+    params[:carbon_offset] = with_carbon_offset
+
     response = EasyPost.make_request(:post, "#{url}/buy", @api_key, params)
     refresh_from(response, @api_key)
 

lib/easypost/util.rb

@@ -37,6 +37,7 @@ module EasyPost::Util
     'Address' => EasyPost::Address,
     'Batch' => EasyPost::Batch,
     'Brand' => EasyPost::Brand,
+    'CarbonOffset' => EasyPost::CarbonOffset,
     'CarrierAccount' => EasyPost::CarrierAccount,
     'CustomsInfo' => EasyPost::CustomsInfo,
     'CustomsItem' => EasyPost::CustomsItem,