agent/tests: Skip test if error is EACCES (permission denied)

On IBM actionspz Z runners, write operations on network interfaces
are not allowed, even for the root user.
This commit skips the `add_update_addresses` test if the operation
fails with EACCES (-13, permission denied).

Signed-off-by: Hyounggyu Choi <Hyounggyu.Choi@ibm.com>

src/agent/src/netlink.rs

@@ -922,6 +922,18 @@ mod tests {
     const TEST_DUMMY_INTERFACE: &str = "dummy_for_arp";
     const TEST_ARP_IP: &str = "192.0.2.127";
 
+    /// Helper function to check if the result is a netlink EACCES error
+    fn is_netlink_permission_error<T>(result: &Result<T>) -> bool {
+        if let Err(e) = result {
+            let error_string = format!("{:?}", e);
+            if error_string.contains("code: Some(-13)") {
+                println!("INFO: skipping test - netlink operations are restricted in this environment (EACCES)");
+                return true;
+            }
+        }
+        false
+    }
+
     #[tokio::test]
     async fn find_link_by_name() {
         let message = Handle::new()
@@ -1045,10 +1057,14 @@ mod tests {
         let lo = handle.find_link(LinkFilter::Name("lo")).await.unwrap();
 
         for network in list {
-            handle
-                .add_addresses(lo.index(), iter::once(network))
-                .await
-                .expect("Failed to add IP");
+            let result = handle.add_addresses(lo.index(), iter::once(network)).await;
+
+            // Skip test if netlink operations are restricted (EACCES = -13)
+            if is_netlink_permission_error(&result) {
+                return;
+            }
+
+            result.expect("Failed to add IP");
 
             // Make sure the address is there
             let result = handle
@@ -1063,10 +1079,14 @@ mod tests {
             assert!(result.is_some());
 
             // Update it
-            handle
-                .add_addresses(lo.index(), iter::once(network))
-                .await
-                .expect("Failed to delete address");
+            let result = handle.add_addresses(lo.index(), iter::once(network)).await;
+
+            // Skip test if netlink operations are restricted (EACCES = -13)
+            if is_netlink_permission_error(&result) {
+                return;
+            }
+
+            result.expect("Failed to delete address");
         }
     }