Set up gRPC Server with ./gradlew -p server clean bootRun.
It starts gRPC Server at localhost:9090.
Optionally, you can start REST client which will accept HTTP requests at localhost:8081, forward them to gRPC Server mentioned above and return you JSON responses.
./gradlew -p client-rest clean bootRun
You can find example requests and more information about client in client-rest folder
There is SonarCloud workflow in this project which builds and runs tests, so generally there is no need to run tests locally.
And still you can run tests both at server and client-rest by ./gradlew clean test.
Note: server tests use testcontainers, so be sure your Docker is running