test: add integration test for DnsPeer

Add dns_peer_sync test that builds a node with a DnsPeer pointing
at the local bitcoind and verifies the node resolves the hostname,
connects, and syncs the chain successfully.

Author: 0xsiddharthks

tests/core.rs

@@ -8,7 +8,7 @@ use bip157::{
     chain::{checkpoints::HeaderCheckpoint, BlockHeaderChanges, ChainState},
     client::Client,
     node::Node,
-    Address, BlockHash, Event, Info, ServiceFlags, Transaction, TrustedPeer, Warning,
+    Address, BlockHash, DnsPeer, Event, Info, ServiceFlags, Transaction, TrustedPeer, Warning,
 };
 use bitcoin::{
     absolute,
@@ -633,6 +633,39 @@ async fn tx_can_broadcast() {
         .unwrap();
 }
 
+#[tokio::test]
+async fn dns_peer_sync() {
+    let (bitcoind, socket_addr) = start_bitcoind(true).unwrap();
+    let rpc = &bitcoind.client;
+    let tempdir = tempfile::TempDir::new().unwrap().path().to_owned();
+    let miner = rpc.new_address().unwrap();
+    mine_blocks(rpc, &miner, 10, 2).await;
+    let best = best_hash(rpc);
+    // Use a DNS peer with a hostname instead of a resolved TrustedPeer.
+    // The hostname is resolved via tokio::net::lookup_host on each connection attempt.
+    let dns_peer = DnsPeer::new(socket_addr.ip().to_string(), socket_addr.port());
+    let builder = bip157::builder::Builder::new(bitcoin::Network::Regtest)
+        .chain_state(ChainState::Checkpoint(HeaderCheckpoint::from_genesis(
+            bitcoin::Network::Regtest,
+        )))
+        .add_dns_peer(dns_peer)
+        .data_dir(tempdir);
+    let (node, client) = builder.build();
+    tokio::task::spawn(async move { node.run().await });
+    let Client {
+        requester,
+        info_rx,
+        warn_rx,
+        event_rx: mut channel,
+    } = client;
+    tokio::task::spawn(async move { print_logs(info_rx, warn_rx).await });
+    sync_assert(&best, &mut channel).await;
+    let cp = requester.chain_tip().await.unwrap();
+    assert_eq!(cp.hash, best);
+    requester.shutdown().unwrap();
+    rpc.stop().unwrap();
+}
+
 #[tokio::test]
 async fn dns_works() {
     let hostname = bip157::lookup_host("seed.bitcoin.sipa.be").await;