assertNotNull(atts);
Iterator<Attachment> itr = atts.iterator();
assertTrue(itr.hasNext());
Attachment a = itr.next();
assertNotNull(a);
InputStream attIs = a.getDataHandler().getInputStream();
assertTrue(((DelegatingInputStream) attIs).getInputStream() instanceof MimeBodyPartInputStream);
assertTrue(((DelegatingInputStream) attBody).getInputStream() instanceof ByteArrayInputStream);
// check the cached output stream