test(trogon-github): cover ServeError display/source and tracing field evaluation

Signed-off-by: Yordis Prieto <yordis.prieto@gmail.com>

Author: yordis

rsworkspace/crates/trogon-github/src/server.rs

@@ -272,6 +272,7 @@ mod tests {
     use hmac::{Hmac, Mac};
     use sha2::Sha256;
     use tower::ServiceExt;
+    use tracing_subscriber::util::SubscriberInitExt;
     use trogon_nats::jetstream::{MockJetStreamContext, MockJetStreamPublisher};
 
     type HmacSha256 = Hmac<Sha256>;
@@ -331,10 +332,31 @@ mod tests {
         builder.body(Body::from(body.to_vec())).unwrap()
     }
 
+    // ── ServeError ─────────────────────────────────────────────────────────
+
+    #[test]
+    fn serve_error_display_and_source() {
+        use async_nats::jetstream::context::{CreateStreamError, CreateStreamErrorKind};
+
+        let io_err =
+            ServeError::Io(std::io::Error::new(std::io::ErrorKind::AddrInUse, "port taken"));
+        assert_eq!(io_err.to_string(), "server IO error: port taken");
+        assert!(std::error::Error::source(&io_err).is_some());
+
+        let prov_err =
+            ServeError::Provision(CreateStreamError::new(CreateStreamErrorKind::EmptyStreamName));
+        assert!(prov_err.to_string().contains("stream provisioning failed"));
+        assert!(std::error::Error::source(&prov_err).is_some());
+
+        let io_err: ServeError = std::io::Error::other("boom").into();
+        assert!(matches!(io_err, ServeError::Io(_)));
+    }
+
     // ── provision ────────────────────────────────────────────────────────────
 
     #[tokio::test]
     async fn provision_creates_stream() {
+        let _guard = tracing_subscriber::fmt().with_test_writer().set_default();
         let js = MockJetStreamContext::new();
         let config = test_config(None);