fix cancellation test on windows by auto assigning port (eclipse-zenoh#2419)

* automatically assign empty port

* fixed bulld

* locator-based port assign

* unused import removed

Author: milyin

zenoh/tests/cancellation.rs

@@ -22,17 +22,31 @@ use zenoh_core::ztimeout;
 
 const TIMEOUT: Duration = Duration::from_secs(60);
 
-async fn create_peer_client_pair(locator: &str) -> (Session, Session) {
+async fn create_peer_client_pair() -> (Session, Session) {
+    // Create a session that listens on an auto assigned TCP port
     let config1 = {
         let mut config = zenoh::Config::default();
         config.scouting.multicast.set_enabled(Some(false)).unwrap();
         config
             .listen
             .endpoints
-            .set(vec![locator.parse().unwrap()])
+            .set(vec!["tcp/127.0.0.1:0".parse().unwrap()])
             .unwrap();
         config
     };
+    let session1 = zenoh::open(config1).await.unwrap();
+
+    // Extract the actual TCP endpoint that session1 is listening on
+    let locator = session1
+        .info()
+        .locators()
+        .await
+        .into_iter()
+        .find(|l| l.protocol().as_str() == "tcp")
+        .expect("Expected at least one TCP locator")
+        .to_string();
+
+    // Create a session that connects to the first session
     let mut config2 = zenoh::Config::default();
     config2.set_mode(Some(WhatAmI::Client)).unwrap();
     config2.scouting.multicast.set_enabled(Some(false)).unwrap();
@@ -41,15 +55,14 @@ async fn create_peer_client_pair(locator: &str) -> (Session, Session) {
         .set_endpoints(ModeDependentValue::Unique(vec![locator.parse().unwrap()]))
         .unwrap();
 
-    let session1 = zenoh::open(config1).await.unwrap();
     let session2 = zenoh::open(config2).await.unwrap();
     (session1, session2)
 }
 
 #[tokio::test(flavor = "multi_thread", worker_threads = 4)]
 async fn test_cancellation_get() {
     zenoh::init_log_from_env_or("error");
-    let (session1, session2) = ztimeout!(create_peer_client_pair("tcp/127.0.0.1:50001"));
+    let (session1, session2) = ztimeout!(create_peer_client_pair());
     let queryable = ztimeout!(session1.declare_queryable("test/query_cancellation")).unwrap();
 
     tokio::time::sleep(Duration::from_secs(1)).await;
@@ -112,7 +125,7 @@ async fn test_cancellation_get() {
 #[tokio::test(flavor = "multi_thread", worker_threads = 4)]
 async fn test_cancellation_liveliness_get() {
     zenoh::init_log_from_env_or("error");
-    let (session1, session2) = ztimeout!(create_peer_client_pair("tcp/127.0.0.1:50002"));
+    let (session1, session2) = ztimeout!(create_peer_client_pair());
     let _token = ztimeout!(session1
         .liveliness()
         .declare_token("test/liveliness_query_cancellation"))
@@ -159,7 +172,7 @@ async fn test_cancellation_liveliness_get() {
 #[tokio::test(flavor = "multi_thread", worker_threads = 4)]
 async fn test_cancellation_querier_get() {
     zenoh::init_log_from_env_or("error");
-    let (session1, session2) = ztimeout!(create_peer_client_pair("tcp/127.0.0.1:50003"));
+    let (session1, session2) = ztimeout!(create_peer_client_pair());
     let queryable = ztimeout!(session1.declare_queryable("test/querier_cancellation")).unwrap();
 
     let querier = ztimeout!(session2.declare_querier("test/querier_cancellation")).unwrap();
@@ -221,7 +234,7 @@ async fn test_cancellation_querier_get() {
 #[tokio::test(flavor = "multi_thread", worker_threads = 4)]
 async fn test_cancellation_does_not_prevent_session_from_close() {
     zenoh::init_log_from_env_or("error");
-    let (session1, session2) = ztimeout!(create_peer_client_pair("tcp/127.0.0.1:50004"));
+    let (session1, session2) = ztimeout!(create_peer_client_pair());
     let cancellation_token = zenoh::cancellation::CancellationToken::default();
 
     let ke = "test/query_cancellation_does_not_prevent_session_from_close";