Differentiate between HTML and plain text e-mails. Use "<br />" inste…

…ad of "\n" for line breaks in HTML e-mails. Added 3 new tests to verify this behaviour.

lib/mail_magnet/tmail_ext.rb

@@ -15,7 +15,8 @@ def override_recipients!(recipients)
     end
     parts << "---------------------------"
 
-    self.body = parts.join("\n") + "\n\n" + self.body
+    line_break = self.content_type =~ /(html)/ ? "<br />" : "\n"
+    self.body = parts.join(line_break) + line_break*2 + self.body
   end
 
   def override(method, recipients)

spec/app_root/app/models/mailer.rb

@@ -7,4 +7,12 @@ def letter
     subject 'Hello Universe!'
   end
 
+  def html_letter
+    recipients 'original.to@example.com'
+    cc 'original.cc@example.com'
+    bcc 'original.bcc@example.com'
+    subject 'Hello Universe!'
+    content_type "text/html"
+  end
+
 end

spec/app_root/app/views/mailer/html_letter.erb

@@ -0,0 +1 @@
+HTMLello!

spec/mail_magnet_spec.rb

@@ -45,4 +45,24 @@
     ActionMailer::Base.deliveries.last.subject.should == 'Hello Universe!'
   end
 
+  it 'should detect the content_type correctly' do
+    ActionMailer::Base.override_recipients = 'overridden.to@example.com'
+    Mailer.deliver_letter
+    ActionMailer::Base.deliveries.last.content_type.should == "text/plain"
+    Mailer.deliver_html_letter
+    ActionMailer::Base.deliveries.last.content_type.should include("text/html") # content_type sometimes ends with "; charset=utf-8"
+  end
+
+  it 'should use "\n" for line breaks in plain text emails' do
+    ActionMailer::Base.override_recipients = 'overridden.to@example.com'
+    Mailer.deliver_letter
+    ActionMailer::Base.deliveries.last.body.should include("To: original.to@example.com\n")
+  end
+
+  it 'should use "<br />" for line breaks in HTML emails' do
+    ActionMailer::Base.override_recipients = 'overridden.to@example.com'
+    Mailer.deliver_html_letter
+    ActionMailer::Base.deliveries.last.body.should include('To: original.to@example.com<br />')
+  end
+
 end