Add networking/port test utils fn(s)

roles/tests-integration/Cargo.toml

@@ -7,6 +7,7 @@ edition = "2021"
 bitcoind = "0.36.0"
 flate2 = "1.0.32"
 minreq = { version = "2.12.0", features = ["https"] }
+once_cell = "1.20.0"
 tar = "0.4.41"
 
 [lib]

roles/tests-integration/tests/common/mod.rs

@@ -1,13 +1,20 @@
 use bitcoind::{bitcoincore_rpc::RpcApi, BitcoinD, Conf};
 use flate2::read::GzDecoder;
+use once_cell::sync::Lazy;
 use std::{
+    collections::HashSet,
     env,
     fs::{create_dir_all, File},
     io::{BufReader, Read},
+    net::TcpListener,
     path::{Path, PathBuf},
+    sync::Mutex,
 };
 use tar::Archive;
 
+// prevents get_available_port from ever returning the same port twice
+static UNIQUE_PORTS: Lazy<Mutex<HashSet<u16>>> = Lazy::new(|| Mutex::new(HashSet::new()));
+
 const VERSION_TP: &str = "0.1.7";
 
 fn download_bitcoind_tarball(download_url: &str) -> Vec<u8> {
@@ -148,3 +155,23 @@ impl TemplateProvider {
             .unwrap();
     }
 }
+
+pub fn is_port_open(address: std::net::SocketAddr) -> bool {
+    TcpListener::bind(address).is_err()
+}
+
+pub fn get_available_port() -> u16 {
+    let mut unique_ports = UNIQUE_PORTS.lock().unwrap();
+
+    loop {
+        let port = TcpListener::bind("127.0.0.1:0")
+            .unwrap()
+            .local_addr()
+            .unwrap()
+            .port();
+        if !unique_ports.contains(&port) {
+            unique_ports.insert(port);
+            return port;
+        }
+    }
+}