tests: add initial tests for rpc methods
tests: add initial tests for rpc methods

Signed-off-by: Florian Scherf <01ea296d94b35b47de034b473506bbbc8961ebf2@pengutronix.de>

pengutronix/aiohttp-json-rpc,pengutronix/aiohttp-json-rpc,pengutronix/aiohttp-json-rpc