testing(fix): Ensure lightclient chainSpec is at least one block old

Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io>

testing/integration-tests/Cargo.toml

@@ -30,6 +30,8 @@ futures = { workspace = true }
 hex = { workspace = true }
 regex = { workspace = true }
 serde = { workspace = true }
+serde_json = { workspace = true }
+jsonrpsee = { workspace = true, features = ["async-client", "client-ws-transport-native-tls"] }
 scale-info = { workspace = true, features = ["bit-vec"] }
 sp-core = { workspace = true }
 syn = { workspace = true }

testing/integration-tests/src/light_client/mod.rs

@@ -117,10 +117,43 @@ async fn dynamic_events(api: &Client) -> Result<(), subxt::Error> {
     Ok(())
 }
 
+/// Fetch the chainSpec from the given url.
+async fn fetch_spec_from_url(url: &str) -> serde_json::Value {
+    // use jsonrpsee::core::client::ClientT;
+    // let client = jsonrpsee_helpers::client(url.as_ref()).await?;
+
+    pub use jsonrpsee::{
+        client_transport::ws::{self, EitherStream, Url, WsTransportClientBuilder},
+        core::client::{Client, ClientT},
+    };
+
+    let url = Url::parse(url).expect("Failed to parse url");
+    let (sender, receiver) = WsTransportClientBuilder::default()
+        .build(url)
+        .await
+        .expect("Failed to connect to the node");
+
+    let client = Client::builder()
+        .max_buffer_capacity_per_subscription(4096)
+        .build_with_tokio(sender, receiver);
+
+    client
+        .request("sync_state_genSyncSpec", jsonrpsee::rpc_params![true])
+        .await
+        .expect("Failed to fetch the chainSpec")
+}
+
 #[tokio::test]
 async fn light_client_testing() -> Result<(), subxt::Error> {
+    let chain_spec = fetch_spec_from_url("wss://rpc.polkadot.io:443").await;
+
+    // Sleep 8 seconds to ensure that a new block is produced for the substrate test node.
+    // Although the block production should be 6 seconds, the CI environment is sometimes slow.
+    // This is a temporary workaround for: https://github.com/smol-dot/smoldot/issues/1562.
+    tokio::time::sleep(std::time::Duration::from_secs(8)).await;
+
     let api: LightClient<PolkadotConfig> = LightClientBuilder::new()
-        .build_from_url("wss://rpc.polkadot.io:443")
+        .build(&chain_spec.to_string())
         .await?;
 
     non_finalized_headers_subscription(&api).await?;