Handle email when written with %2B instead of + (#128)

app/mailboxes/newsletter_mailbox.rb

@@ -46,6 +46,6 @@ def recipients
     # NOTE: `mail.received` can be an instance of `Mail::ReceivedField` or an array of instances
     received = Array.wrap(mail.received).first&.decoded&.match(/<([a-z@\d\.\-\+]+)>/i)
     arr.push(received[1]) if received.present?
-    arr
+    arr.map { |email| email.gsub('%2B', '+') }
   end
 end

test/mailboxes/newsletter_mailbox_test.rb

@@ -56,6 +56,21 @@ class NewsletterMailboxTest < ActionMailbox::TestCase
     assert_equal 'Hello world!', Entry.last.title
   end
 
+  test 'should find newsletter if plus was written as `%2B`' do
+    assert_difference 'Entry.count' do
+      receive_inbound_email_from_mail do |mail|
+        mail.to '[email protected]'
+        mail.cc = "newsletter-#{@newsletter.id}%2B#{@newsletter.public_id}@example.com"
+        mail.from '"me" <[email protected]>'
+        mail.subject 'Hello world!'
+        mail.body 'Hello?'
+      end
+    end
+
+    assert_equal 'me <[email protected]>', Entry.last.author
+    assert_equal 'Hello world!', Entry.last.title
+  end
+
   test 'should bounce email when public id is mismatched' do
     assert_no_difference 'Entry.count' do
       receive_inbound_email_from_mail do |mail|