Acceptable to connect two different SERCOM ports to test serial coms

Hello, My resources to test serial protocols is limited as is my ability to source equipment, but I can get my hands on a soldering iron. I need to test the serial output of a micro controller (SAML21G17B) somehow so I figured it might be okay to connect two different serial ports as long as there is an interrupt for the receiver to prevent the transmitter from overflowing the data register. Has anyone tried this? Should I find an alternative? It takes quite a while to get anything to my current location (2 or so weeks).