Add simple test ensuring we can restart from a VSS backend

This is close to the backwards compatibility test we just added for v0,
now just making sure we can actually read the data we persisted with our
current (V1+) code.

Co-authored by Claude AI

Author: tnull

tests/integration_tests_vss.rs

@@ -130,3 +130,69 @@ async fn vss_v0_schema_backwards_compatibility() {
 
 	node_new.stop().unwrap();
 }
+
+#[tokio::test(flavor = "multi_thread", worker_threads = 1)]
+async fn vss_node_restart() {
+	let (bitcoind, electrsd) = common::setup_bitcoind_and_electrsd();
+	let esplora_url = format!("http://{}", electrsd.esplora_url.as_ref().unwrap());
+	let vss_base_url = std::env::var("TEST_VSS_BASE_URL").unwrap();
+
+	let rand_suffix: String =
+		(0..7).map(|_| rng().sample(rand::distr::Alphanumeric) as char).collect();
+	let store_id = format!("restart_test_{}", rand_suffix);
+	let storage_path = common::random_storage_path().to_str().unwrap().to_owned();
+	let seed_bytes = [42u8; 64];
+
+	// Setup initial node and fund it.
+	let (expected_balance_sats, expected_node_id) = {
+		let mut builder = Builder::new();
+		builder.set_network(bitcoin::Network::Regtest);
+		builder.set_storage_dir_path(storage_path.clone());
+		builder.set_entropy_seed_bytes(seed_bytes);
+		builder.set_chain_source_esplora(esplora_url.clone(), None);
+		let node = builder
+			.build_with_vss_store_and_fixed_headers(
+				vss_base_url.clone(),
+				store_id.clone(),
+				HashMap::new(),
+			)
+			.unwrap();
+
+		node.start().unwrap();
+		let addr = node.onchain_payment().new_address().unwrap();
+		common::premine_and_distribute_funds(
+			&bitcoind.client,
+			&electrsd.client,
+			vec![addr],
+			bitcoin::Amount::from_sat(100_000),
+		)
+		.await;
+		node.sync_wallets().unwrap();
+
+		let balance = node.list_balances().spendable_onchain_balance_sats;
+		assert!(balance > 0);
+		let node_id = node.node_id();
+
+		node.stop().unwrap();
+		(balance, node_id)
+	};
+
+	// Verify node can be restarted from VSS backend.
+	let mut builder = Builder::new();
+	builder.set_network(bitcoin::Network::Regtest);
+	builder.set_storage_dir_path(storage_path);
+	builder.set_entropy_seed_bytes(seed_bytes);
+	builder.set_chain_source_esplora(esplora_url, None);
+
+	let node = builder
+		.build_with_vss_store_and_fixed_headers(vss_base_url, store_id, HashMap::new())
+		.unwrap();
+
+	node.start().unwrap();
+	node.sync_wallets().unwrap();
+
+	assert_eq!(expected_node_id, node.node_id());
+	assert_eq!(expected_balance_sats, node.list_balances().spendable_onchain_balance_sats);
+
+	node.stop().unwrap();
+}