You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: tests.rs
    path of file: ./repos/grpc-rs/interop/tests
    
    the code of the file until where you have to start completion: // Copyright 2019 TiKV Project Authors. Licensed under Apache-2.0.

extern crate grpcio as grpc;
extern crate grpcio_proto as grpc_proto;
extern crate interop;

macro_rules! mk_test {
    ($case_name:ident, $func:ident, $use_tls:expr) => {
        #[test]
        fn $case_name() {
            let env = Arc::new(Environment::new(2));

            let service = create_test_service(InteropTestService);
            let mut server = ServerBuilder::new(env.clone())
                .register_service(service)
                .build()
                .unwrap();
            let creds = if $use_tls {
                util::create_test_server_credentials()
            } else {
                grpcio::ServerCredentials::in
    
        fn $case_name() {
            let env = Arc::new(Environment::new(2));

            let service = create_test_service(InteropTestService);
            let mut server = ServerBuilder::new(env.clone())
                .register_service(service)
                .build()
                .unwrap();
            let creds = if $use_tls {
                util::create_test_server_credentials()
            } else {
                grpcio::ServerCredentials::insecure()
            };
            let port = server.add_listening_port("127.0.0.1:0", creds).unwrap();
            server.start();

            let mut builder =
                ChannelBuilder::new(env.clone()).override_ssl_target("foo.test.google.fr");
            if $use_tls {
                let creds = util::create_test_channel_credentials();
                builder = builder.set_credentials(creds);
            }
            let channel = builder.connect(&format!("127.0.0.1:{port}"));
            let client = Client::new(channel);
            block_on(client.$func()).unwrap();
        }