raise error when email address is invalid

lib/mailtrap/mail.rb

@@ -4,16 +4,19 @@
 
 require_relative 'mail/base'
 require_relative 'mail/from_template'
+require_relative 'errors'
 
 module Mailtrap
   module Mail
     class << self
+      # @param message [Mail::Message]
+      # @return [Mailtrap::Mail::Base]
       def from_message(message) # rubocop:disable Metrics/AbcSize, Metrics/MethodLength
         Mailtrap::Mail::Base.new(
-          from: prepare_addresses(address_list(message['from'])&.addresses).first,
-          to: prepare_addresses(address_list(message['to'])&.addresses),
-          cc: prepare_addresses(address_list(message['cc'])&.addresses),
-          bcc: prepare_addresses(address_list(message['bcc'])&.addresses),
+          from: prepare_addresses(address_list(message, 'from')&.addresses).first,
+          to: prepare_addresses(address_list(message, 'to')&.addresses),
+          cc: prepare_addresses(address_list(message, 'cc')&.addresses),
+          bcc: prepare_addresses(address_list(message, 'bcc')&.addresses),
           subject: message.subject,
           text: prepare_text_part(message),
           html: prepare_html_part(message),
@@ -50,10 +53,21 @@ def from_message(message) # rubocop:disable Metrics/AbcSize, Metrics/MethodLengt
 
       HEADERS_TO_REMOVE = (SPECIAL_HEADERS + ACTIONMAILER_ADDED_HEADERS).freeze
 
-      def address_list(header)
-        header.respond_to?(:element) ? header.element : header&.address_list
+      # @param message [Mail::Message]
+      # @param header_name [String]
+      # @return [Mail::AddressList, nil]
+      def address_list(message, header_name)
+        field = message[header_name]
+        return nil unless field
+
+        unless field.errors.empty?
+          raise Mailtrap::Error, ["failed to parse '#{header_name}': '#{field.unparsed_value}'"]
+        end
+
+        field.respond_to?(:element) ? field.element : field.address_list
       end
 
+      # @param addresses [Array<Mail::Address>, nil]
       def prepare_addresses(addresses)
         Array(addresses).map { |address| prepare_address(address) }
       end
@@ -66,6 +80,7 @@ def prepare_headers(message)
           .compact
       end
 
+      # @param address [Mail::Address]
       def prepare_address(address)
         {
           email: address.address,

spec/mailtrap/mail_spec.rb

@@ -142,5 +142,15 @@
       # (There will be a "'from' is required" error from the server)
       its(:from) { is_expected.to be_nil }
     end
+
+    %i[from to cc bcc].each do |header|
+      context "when '#{header}' is invalid" do
+        let(:message_params) { super().merge(header => 'invalid [email protected]') }
+
+        it 'raises an error' do
+          expect { mail }.to raise_error(Mailtrap::Error, "failed to parse '#{header}': 'invalid [email protected]'")
+        end
+      end
+    end
   end
 end