Respect smtp_envelope_to when sending MIME messages

lib/mailgunner/client/messages.rb

@@ -15,7 +15,7 @@ def send_message(attributes = ATTRIBUTES)
     end
 
     def send_mime(mail)
-      to = ['to', Array(mail.destinations).join(',')]
+      to = ['to', Array(mail.smtp_envelope_to).join(',')]
 
       message = ['message', mail.encoded, {filename: 'message.mime'}]
 

spec/mailgunner/client_spec.rb

@@ -131,6 +131,22 @@ def stub(http_method, url, body: nil, headers: nil)
 
       client.send_mime(mail)
     end
+
+    it 'overrides recipients with smtp_envelope_to when present' do
+      mail.to = 'alice@example.com, john@example.com'
+      mail.cc = 'carol@example.com, eve@example.com'
+      mail.bcc = 'dave@example.com, frank@example.com'
+
+      mail.smtp_envelope_to = 'alice@example.com, carol@example.com, dave@example.com'
+
+      stub(:post, "#{base_url}/v3/#{domain}/messages.mime")
+
+      recipients = 'alice@example.com, carol@example.com, dave@example.com'
+
+      Net::HTTP::Post.any_instance.expects(:set_form).with(includes(['to', recipients]), 'multipart/form-data')
+
+      client.send_mime(mail)
+    end
   end
 
   describe '#delete_message' do