'Compression isn\'t performed on responses that are already compressed.'

def test_no_compress_compressed_response(self):

    self.resp['Content-Encoding'] = 'deflate'
    r = GZipMiddleware().process_response(self.req, self.resp)
    self.assertEqual(r.content, self.compressible_string)
    self.assertEqual(r.get('Content-Encoding'), 'deflate')
