add integration test and doc comment for get_zmq_notifications

Author: antonilol

client/src/client.rs

@@ -1264,6 +1264,7 @@ pub trait RpcApi: Sized {
         self.call("scantxoutset", &["start".into(), into_json(descriptors)?])
     }
 
+    /// Returns information about the active ZeroMQ notifications
     fn get_zmq_notifications(&self) -> Result<Vec<json::GetZmqNotificationsResult>> {
         self.call("getzmqnotifications", &[])
     }

integration_test/src/main.rs

@@ -226,6 +226,7 @@ fn main() {
     test_add_ban(&cl);
     test_set_network_active(&cl);
     test_get_index_info(&cl);
+    test_get_zmq_notifications(&cl);
     test_stop(cl);
 }
 
@@ -1422,6 +1423,13 @@ fn test_get_index_info(cl: &Client) {
     }
 }
 
+fn test_get_zmq_notifications(cl: &Client) {
+    let zmq_info = cl.get_zmq_notifications().unwrap();
+
+    // no zmq subscribers are configured
+    assert!(zmq_info.is_empty());
+}
+
 fn test_stop(cl: Client) {
     println!("Stopping: '{}'", cl.stop().unwrap());
 }