rust testcontainer framework

[kpwebb]

Here's my initial shot at a testcontainers implementation for the Rust SDK.

I've got the core functionality working, but wanted to share while in progress to see if adding a new "restate-test-utils" crate to the SDK is ok. Also wanted to solicit feedback on ways to extend the test implementation (e.g. mirroring Temporal's approach), per discussions on Discord.

Here's the current test implementation for a service as defined in tests/test_container.rs

#[tokio::test]
async fn test_container_image() {

    let test_container = TestContainer::new().await.unwrap();

    // uses higher port number to avoid collisions
    // with non-test instances running locally
    let host_port:u16 = 19080;
    let host_address = format!("0.0.0.0:{}", host_port);

    println!("starting host");
    // boot restate server
    tokio::spawn(async move {
        HttpServer::new(
            Endpoint::builder()
                .bind(MyServiceImpl.serve())
                .build(),
        ).listen_and_serve(host_address.parse().unwrap()).await;
    });

    use restate_sdk::service::Discoverable;
    let my_service:Service = ServeMyService::<MyServiceImpl>::discover();

    let registered = test_container.register(host_port).await;
    assert!(registered.is_ok());

    TestContainer::delay(1000).await;

    let response = test_container.invoke(my_service, "my_handler".to_string()).await;

}

[slinkydeveloper]

This is awesome, i'll give a look in the next days!

[slinkydeveloper]

just left few initial comments, thanks for the contribution!

[kpwebb]

@slinkydeveloper thanks for the feedback! Just pushed an update that captures the above. Here's the new test implementation:

#[tokio::test]
async fn test_container_image() {

    let mut test_container = TestContainer::new("docker.io/restatedev/restate", "latest").await.unwrap();

    let endpoint = Endpoint::builder()
                    .bind(MyServiceImpl.serve())
                    .build();

    test_container.serve_endpoint(endpoint).await;

    // optionally insert a delays via tokio sleep
    TestContainer::delay(1000).await;

    // optionally call invoke on service handlers
    use restate_sdk::service::Discoverable;
    let my_service:Service = ServeMyService::<MyServiceImpl>::discover();
    let invoke_response = test_container.invoke(my_service, "my_handler").await;

    assert!(invoke_response.is_ok());

    println!("invoke response:");
    println!("{}", invoke_response.unwrap().text().await.unwrap());

}

[slinkydeveloper]

Hi! Thanks again for the contribution, I had some time to take a look, it's getting there, I think the API needs another pass

[slinkydeveloper]

This is awesome. Run just check locally to fix linting/formatting issues and then we should be good to go!

[kpwebb]

thanks again for the recs and sorry for not running lint/fmt! should be good to go now

[slinkydeveloper]

One minor nit, and I merge