Implement return path from individual message

lib/sparkpost_rails/delivery_method.rb

@@ -189,10 +189,7 @@ def prepare_options_from mail, sparkpost_data
       prepare_open_tracking_from sparkpost_data
       prepare_click_tracking_from sparkpost_data
       prepare_campaign_id_from sparkpost_data
-
-      unless SparkPostRails.configuration.return_path.nil?
-        @data[:return_path] = SparkPostRails.configuration.return_path
-      end
+      prepare_return_path_from mail
 
     end
 
@@ -238,6 +235,18 @@ def prepare_campaign_id_from sparkpost_data
       end
     end
 
+    def prepare_return_path_from mail
+      return_path = SparkPostRails.configuration.return_path
+
+      unless mail.return_path.nil?
+        return_path = mail.return_path
+      end
+
+      if return_path
+        @data[:return_path] = return_path
+      end
+    end
+
     def prepare_headers
       @headers = {
         "Authorization" => SparkPostRails.configuration.api_key,

spec/return_path_spec.rb

@@ -0,0 +1,50 @@
+require 'spec_helper'
+
+describe SparkPostRails::DeliveryMethod do
+
+  before(:each) do
+    SparkPostRails.configuration.set_defaults
+    @delivery_method = SparkPostRails::DeliveryMethod.new
+  end
+
+  context "Return Path" do
+    it "handles return path set in the configuration" do
+      SparkPostRails.configure do |c|
+        c.return_path = "[email protected]"
+      end
+
+      test_email = Mailer.test_email
+      @delivery_method.deliver!(test_email)
+
+      expect(@delivery_method.data[:return_path]).to eq('[email protected]')
+    end
+
+    it "handles return path on an individual message" do
+      test_email = Mailer.test_email return_path: "[email protected]"
+
+      @delivery_method.deliver!(test_email)
+
+      expect(@delivery_method.data[:return_path]).to eq('[email protected]')
+    end
+
+    it "handles the value on an individual message overriding configuration" do
+      SparkPostRails.configure do |c|
+        c.return_path = "[email protected]"
+      end
+
+      test_email = Mailer.test_email return_path: "[email protected]"
+
+      @delivery_method.deliver!(test_email)
+
+      expect(@delivery_method.data[:return_path]).to eq('[email protected]')
+    end
+
+    it "handles a default setting of none" do
+      test_email = Mailer.test_email
+      @delivery_method.deliver!(test_email)
+
+      expect(@delivery_method.data.has_key?(:return_path)).to eq(false)
+    end
+
+  end
+end