Add a test to check that anything in the MIME epilogue is ignored

There is currently a difference in behaviour in the parsing
of nested MIME multipart attachments between the Mail and
TMail based backends.  This commit adds a test that will
pass if the behaviour is the same as the the old (TMail-based)
version, which I believe is correct according to RFC 1521.
The example email has a PNG attachment after the final MIME
boundary, and the RFC says that anything after the final
boundary ("the epilogue") should be ignored.

1 files changed, 11 insertions, 0 deletions

diff --git a/spec/lib/mail_handler/mail_handler_spec.rb b/spec/lib/mail_handler/mail_handler_spec.rb
index 487f3bf0d..eca5e2dd4 100644
--- a/spec/lib/mail_handler/mail_handler_spec.rb
+++ b/spec/lib/mail_handler/mail_handler_spec.rb
@@ -310,6 +310,17 @@ describe 'when getting attachment attributes' do
         attributes.length.should == 2
     end
 
+    it 'should ignore anything beyond the final MIME boundary' do
+        # This example raw email has a premature closing boundary for
+        # the outer multipart/mixed - my reading of RFC 1521 is that
+        # the "epilogue" beyond that should be ignored.
+        # See https://github.com/mysociety/alaveteli/issues/922 for
+        # more discussion.
+        mail = get_fixture_mail('nested-attachments-premature-end.email')
+        attributes = MailHandler.get_attachment_attributes(mail)
+        attributes.length.should == 3
+    end
+
     it 'should ignore a TNEF attachment with no usable contents' do
         # FIXME: "no usable contents" is slightly misleading.  The
         # attachment in this example email does have usable content in