conn = graph.connect_ports(src.output_ports['out'], sink.input_ports['in'])
self.assertEqual(conn.upstream_port.addr, src.output_ports['out'].addr)
self.assertIs(type(conn.upstream_port), bt2_port._OutputPortConst)
conn = graph.connect_ports(src.output_ports['out'], sink.input_ports['in'])
self.assertEqual(conn.upstream_port.addr, src.output_ports['out'].addr)
self.assertIs(type(conn.upstream_port), bt2_port._OutputPortConst)