Testing email receive for appengine

It's not too obvious how to test email receive handlers in Appengine.  The important observation is that the handlers take HTTP POSTs with multipart/form-data encoded data.  In python you can build an email to be handled with the following code:

from email.message import Message 

def test_email(self):
  body = Message()
  body.add_header('to', 'test-unknown@other-app.com')
  body.add_header('from', 'test@app.com')
  body.add_header('Content-Type', 'multipart/alternative', boundary=self.boundary)
  text = Message()
  text['content-type'] = 'text/plain'
  text.set_payload('I am I! Don Quixote!  The man of La Mancha!')
  body.attach(text)

  post(payload=body.as_string())