Companion for https://github.com/paritytech/substrate/pull/12147 (#1587)

* Companion for https://github.com/paritytech/substrate/pull/12147

* update lockfile for {"substrate", "polkadot"}

* Fix tests

Co-authored-by: parity-processbot <>

cumulus/polkadot-parachain/tests/common.rs

@@ -117,6 +117,7 @@ pub fn find_ws_url_from_output(read: impl Read + Send) -> (String, String) {
 				line.expect("failed to obtain next line from stdout for WS address discovery");
 
 			data.push_str(&line);
+			data.push_str("\n");
 
 			// does the line contain our port (we expect this specific output from substrate).
 			let sock_addr = match line.split_once("Running JSON-RPC WS server: addr=") {
@@ -126,7 +127,10 @@ pub fn find_ws_url_from_output(read: impl Read + Send) -> (String, String) {
 
 			Some(format!("ws://{}", sock_addr))
 		})
-		.expect("We should get a WebSocket address");
+		.unwrap_or_else(|| {
+			eprintln!("Output:\n{}", data);
+			panic!("We should get a WebSocket address")
+		});
 
 	(ws_url, data)
 }

cumulus/polkadot-parachain/tests/purge_chain_works.rs

@@ -28,8 +28,9 @@ async fn purge_chain_works() {
 	// Check that both databases are deleted
 
 	let base_dir = tempdir().expect("could not create a temp dir");
+	let base_dir_path = format!("{}/polkadot", base_dir.path().display());
 
-	let args = &["--", "--dev"];
+	let args = &["--", "--dev", "-d", &base_dir_path];
 
 	common::run_node_for_a_while(base_dir.path(), args, SIGINT).await;