**1. Building:**
The service was successfully built with the CI process or can be built manually using the `cargo build` command in `services/tunnelbroker` directory.
**2. gRPC testings:**
Run the service using the `cargo run` command. Open the gRPC client and call the `SessionSignature` request with the valid `deviceID`.
For example:
```
{
"deviceID": "mobile:foS4IBADcn3uUNF8DEoH2jj6b8hujMsKUtNAKhJID4U50oalGWyg9rdLpgJwlmRy"
}
```
The expected result should be the `toSign` generated string from the server:
```
{
"toSign": "7u1iiQNBlrsn0qy9BhlX8BJxttS6cBNnuCtJR1N9Mp8up56Qc4BEZWc9OvJYjlou"
}
```