Build the container with docker compose build
Then run test with docker compose run --rm harness
This project should give you a head start if you are implementing Inventory Service plugin in Java.
Please read the documentation if you haven't done so.
Main class, if launched with appropriate parameters, will invoke all the APIs your plugin should implement as per contract.
Note that this harness is not extensive: there may be code paths which may not be covered by this, especially since this tool uses randomization a lot.
E.g. it uses randomly available product and its availability for making a reservation/booking.
Requires Java 8.