test_proxy_connection: make test more robust (#390)

- Support running on macos with podman (this probably also fixes it to work with docker as well).
   This is done by using a dedicated network name and by dynamically finding the host ip.
   In macos, both podman & docker are running inside a Linux VM, so it is essential to find a real IP
   associated with the macos itself.

 - Run the mock TCP server on a dynamic port. This avoid flakiness in case the port is already in use.

Cargo.toml

@@ -77,6 +77,10 @@ rstest = "0.23.0"
 serial_test = "3.2.0"
 derive_more = { version = "1.0.0", features = ["from"] }
 
+[target.'cfg(target_os = "macos")'.dev-dependencies]
+get_if_addrs = "0.5.3"
+
+
 [profile.release]
 lto = "fat"
 panic = "abort"

src/protocols/tcp/server.rs

@@ -233,7 +233,7 @@ mod tests {
     use super::*;
     use futures_util::pin_mut;
     use std::borrow::Cow;
-    use std::net::SocketAddr;
+    use std::net::IpAddr;
     use testcontainers::core::WaitFor;
     use testcontainers::runners::AsyncRunner;
     use testcontainers::{ContainerAsync, Image, ImageExt};
@@ -263,15 +263,30 @@ mod tests {
 
     #[tokio::test]
     async fn test_proxy_connection() {
-        let server_addr: SocketAddr = "[::1]:1236".parse().unwrap();
-        let server = TcpListener::bind(server_addr).await.unwrap();
+        let (network_name, host) = if cfg!(not(target_os = "macos")) {
+            ("host", "127.0.0.1".parse::<IpAddr>().unwrap())
+        } else {
+            let host = get_if_addrs::get_if_addrs()
+                .unwrap()
+                .into_iter()
+                .map(|iface| iface.addr.ip())
+                .find(|ip| ip.is_ipv4() && !ip.is_loopback())
+                .unwrap();
+            ("wstunnel_test_proxy_connection", host)
+        };
+
+        let mitm_proxy: ContainerAsync<MitmProxy> = MitmProxy.with_network(network_name).start().await.unwrap();
+
+        let proxy_port = mitm_proxy.get_host_port_ipv4(8080).await.unwrap();
 
-        let _mitm_proxy: ContainerAsync<MitmProxy> = MitmProxy.with_network("host".to_string()).start().await.unwrap();
+        // bind to a dynamic port - avoid conflicts
+        let server = TcpListener::bind((host, 0)).await.unwrap();
+        let server_port = server.local_addr().unwrap().port();
 
         let mut client = connect_with_http_proxy(
-            &"http://localhost:8080".parse().unwrap(),
-            &Host::Domain("[::1]".to_string()),
-            1236,
+            &Url::parse(&format!("http://127.0.0.1:{proxy_port}")).unwrap(),
+            &Host::Domain(host.to_string()),
+            server_port,
             None,
             Duration::from_secs(1),
             &DnsResolver::System,