I have been dealing with this same issue recently of wanting to wait for handle_contiue to complete before I start testing my server.
I found a the simplest solution was to just put in a call to the server since the message won’t be processed until after the continue has completed. I didn’t want to wrote code in a handle_call just for testing so I used the erlang sys module for this since it provides convince debug functions for working with processes. I found calling :sys.get_state(server_pid) often did the trick. This way I don’t have to use some arbitrary sleep duration to try and guess how long it will take.
