Serialize the mdns tests and relax push-test deadlines

push_hands_content_to_trusted_peer failed on CI: the test harness runs
lan_trust tests in parallel, so the three mdns-dependent tests spawn
six daemons at once — multicast timing and two runner cores don't
survive that. A process-wide mutex runs them one at a time, and the
push deadlines now match the 60s convention of the other transfer
tests.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

varde-daemon/tests/lan_trust.rs

@@ -78,6 +78,11 @@ fn wait_complete(socket: &Path, hash: &str, timeout: Duration) -> bool {
     false
 }
 
+/// mdns tests spawn two daemons each and depend on multicast timing;
+/// run them one at a time so they don't starve each other on small CI
+/// runners.
+static MDNS_SERIAL: std::sync::Mutex<()> = std::sync::Mutex::new(());
+
 /// Re-target a ticket at another hash on the same provider: what an
 /// attacker who learned a hash out of band would hand to their daemon.
 fn forge_ticket(real_ticket: &str, target_hash: &str) -> String {
@@ -225,6 +230,7 @@ fn subscribe_streams_progress_and_completion() {
 /// sibling process.
 #[test]
 fn overlapping_pins_auto_sync_via_lan_discovery() {
+    let _serial = MDNS_SERIAL.lock().unwrap_or_else(|e| e.into_inner());
     let dir_a = tempfile::tempdir().unwrap();
     let dir_b = tempfile::tempdir().unwrap();
     let a = support::spawn_daemon_with_env(dir_a.path(), &[("VARDE_DISCOVERY", "true")]);
@@ -302,6 +308,7 @@ fn wait_peer_connected(client: &mut support::Client, timeout: Duration) -> bool
 /// accepted, so the content survives gc and lists as a pin.
 #[test]
 fn push_hands_content_to_trusted_peer() {
+    let _serial = MDNS_SERIAL.lock().unwrap_or_else(|e| e.into_inner());
     let dir_a = tempfile::tempdir().unwrap();
     let dir_b = tempfile::tempdir().unwrap();
     let a = support::spawn_daemon_with_env(dir_a.path(), &[("VARDE_DISCOVERY", "true")]);
@@ -349,13 +356,13 @@ fn push_hands_content_to_trusted_peer() {
     }
 
     // The receiver has the bytes, and pinned them.
-    if !wait_complete(&b.socket, &hash, Duration::from_secs(30)) {
+    if !wait_complete(&b.socket, &hash, Duration::from_secs(60)) {
         let reply = client_b.request(&Request::Status {
             hash: Some(hash.clone()),
         });
         panic!("pushed content not complete on receiver; status: {reply:?}");
     }
-    let deadline = Instant::now() + Duration::from_secs(10);
+    let deadline = Instant::now() + Duration::from_secs(30);
     loop {
         let reply = client_b.request(&Request::List {});
         if let Some(ResponseData::Pins { pins }) = &reply.data {
@@ -383,6 +390,7 @@ fn push_hands_content_to_trusted_peer() {
 /// the push, even though the sender trusts the receiver.
 #[test]
 fn push_rejected_without_receiver_trust() {
+    let _serial = MDNS_SERIAL.lock().unwrap_or_else(|e| e.into_inner());
     let dir_a = tempfile::tempdir().unwrap();
     let dir_b = tempfile::tempdir().unwrap();
     let a = support::spawn_daemon_with_env(dir_a.path(), &[("VARDE_DISCOVERY", "true")]);