Use dockertest for the newly added serai-client-serai test

tests/substrate/src/lib.rs

@@ -0,0 +1,42 @@
+use std::time::Duration;
+
+use serai_client_serai::Serai;
+
+use dockertest::{StartPolicy, PullPolicy, Image, TestBodySpecification, DockerOperations};
+
+pub struct Handle(String);
+
+pub fn composition(name: &str, logs_path: String) -> (TestBodySpecification, Handle) {
+  let handle = serai_docker_tests::handle(&format!("serai-{name}"));
+  serai_docker_tests::build("serai".to_string());
+  (
+    TestBodySpecification::with_image(
+      Image::with_repository("serai-dev-serai").pull_policy(PullPolicy::Never),
+    )
+    .replace_env(
+      [("SERAI_NAME".to_string(), name.to_lowercase()), ("KEY".to_string(), " ".to_string())]
+        .into(),
+    )
+    .set_start_policy(StartPolicy::Strict)
+    .set_publish_all_ports(true)
+    .set_handle(handle.clone())
+    .set_log_options(Some(serai_docker_tests::log_options(logs_path))),
+    Handle(handle),
+  )
+}
+
+pub async fn rpc(ops: &DockerOperations, handle: Handle) -> Serai {
+  let serai_rpc = ops.handle(&handle.0).host_port(9944).unwrap();
+  let serai_rpc = format!("http://{}:{}", serai_rpc.0, serai_rpc.1);
+
+  // If the RPC server has yet to start, sleep for up to 60s until it does
+  let client = Serai::new(serai_rpc.clone()).unwrap();
+  for _ in 0 .. 180 {
+    tokio::time::sleep(Duration::from_secs(1)).await;
+    if client.block_by_number(0).await.is_err() {
+      continue;
+    }
+    return client;
+  }
+  panic!("serai RPC server wasn't available after 60s");
+}