testing: Wait for more blocks for the lightclient init

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

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

@@ -10,4 +10,4 @@ mod wait_for_blocks;
 pub use context::*;
 pub use node_proc::TestNodeProcess;
 pub use tx_retries::*;
-pub use wait_for_blocks::wait_for_blocks;
+pub use wait_for_blocks::*;

testing/integration-tests/src/utils/node_proc.rs

@@ -241,7 +241,10 @@ async fn build_light_client<T: Config>(proc: &SubstrateNode) -> Result<LightClie
         .await
         .map_err(|err| format!("Failed to connect to node rpc at {ws_url}: {err}"))?;
 
-    super::wait_for_blocks(&client).await;
+    // Wait for at least 3 blocks before starting the light client.
+    // Otherwise, the lightclient might error with
+    // `"Error when retrieving the call proof: No node available for call proof query"`.
+    super::wait_for_number_of_blocks(&client, 3).await;
 
     // Step 2. Construct the light client.
     // P2p bootnode.

testing/integration-tests/src/utils/wait_for_blocks.rs

@@ -8,9 +8,18 @@ use subxt::{client::OnlineClientT, Config};
 /// wait for one more finalized block to be produced, which is important because
 /// the first finalized block doesn't have much state etc associated with it.
 pub async fn wait_for_blocks<C: Config>(api: &impl OnlineClientT<C>) {
-    let mut sub = api.blocks().subscribe_finalized().await.unwrap();
-    // The current finalized block:
-    sub.next().await;
-    // The next one:
-    sub.next().await;
+    // The current finalized block and the next block.
+    wait_for_number_of_blocks(api, 2).await;
+}
+
+/// Wait for a number of blocks to be produced.
+pub async fn wait_for_number_of_blocks<C: Config>(
+    api: &impl OnlineClientT<C>,
+    number_of_blocks: usize,
+) {
+    let mut sub = api.blocks().subscribe_finalized().await.unwrap();
+
+    for _ in 0..number_of_blocks {
+        sub.next().await;
+    }
 }