Thanks for the help!
I had a look into some of the code, and was able to find the correct commands which let me load the code path into the slave:
:os.cmd('epmd -daemon')
Node.start(:master@localhost, :shortnames)
:slave.start(:localhost, 'slave')
:rpc.block_call(:test@localhost, :code, :add_paths, [:code.get_path()])
...
Node.spawn(:slave@localhost, fn -> IO.puts "test" end)
...
#PID<10741.85.0>
iex(master@localhost)9> test
It worked!
