Added a .multipart matcher

lib/shoulda/matchers/action_mailer/have_sent_email.rb

@@ -41,12 +41,18 @@ module Shoulda # :nodoc:
           self
         end
 
+        def multipart(flag = true)
+          @multipart = !!flag
+          self
+        end
+
         def matches?(subject)
           ::ActionMailer::Base.deliveries.each do |mail|
             @subject_failed = !regexp_or_string_match(mail.subject, @email_subject) if @email_subject
             @body_failed = !body_match(mail, @body) if @body
             @sender_failed = !regexp_or_string_match_in_array(mail.from, @sender) if @sender
             @recipient_failed = !regexp_or_string_match_in_array(mail.to, @recipient) if @recipient
+            @multipart_failed = mail.multipart? != @multipart if defined?(@multipart)
             return true unless anything_failed?
           end
 
@@ -78,6 +84,7 @@ module Shoulda # :nodoc:
           expectation << " with body #{@body.inspect}" if @body_failed
           expectation << " from #{@sender.inspect}" if @sender_failed
           expectation << " to #{@recipient.inspect}" if @recipient_failed
+          expectation << " #{!@multipart && 'not '}being multipart" if @multipart_failed
           expectation << "\nDeliveries:\n#{inspect_deliveries}"
         end
 
@@ -88,7 +95,7 @@ module Shoulda # :nodoc:
         end
 
         def anything_failed?
-          @subject_failed || @body_failed || @sender_failed || @recipient_failed
+          @subject_failed || @body_failed || @sender_failed || @recipient_failed || @multipart_failed
         end
 
         def regexp_or_string_match(a_string, a_regexp_or_string)

spec/shoulda/action_mailer/have_sent_email_spec.rb

@@ -11,8 +11,11 @@ describe Shoulda::Matchers::ActionMailer::HaveSentEmailMatcher do
         def the_email
           mail :from    => "do-not-reply@example.com",
                :to      => "myself@me.com",
-               :subject => "This is spam",
-               :body    => "Every email is spam."
+               :subject => "This is spam" do |format|
+
+            format.text { render :text => "Every email is spam." }
+            format.html { render :text => "<h1>HTML is spam.</h1><p>Notably.</p>" }
+          end
         end
       end
       add_mail_to_deliveries
@@ -55,6 +58,13 @@ describe Shoulda::Matchers::ActionMailer::HaveSentEmailMatcher do
       matcher.failure_message.should =~ /Expected sent email to/
     end
 
+    it "accepts sent-email when it is multipart" do
+      should have_sent_email.multipart
+      matcher = have_sent_email.multipart(false)
+      matcher.matches?(nil)
+      matcher.failure_message.should =~ /Expected sent email not being multipart/
+    end
+
     it "lists all the deliveries within failure message" do
       add_mail_to_deliveries