swarm-matrix-client: document the room calls; test the whoami refusal

hive-matrix-mcp/src/client.rs

@@ -529,4 +529,41 @@ mod tests {
         ));
         assert!(calls(&fake).is_empty());
     }
+
+    /// Serve `status` and `body` for every request on loopback; returns the
+    /// base URL.
+    async fn stub_homeserver(status: u16, body: &'static str) -> String {
+        let app = axum::Router::new().fallback(move || async move {
+            (
+                axum::http::StatusCode::from_u16(status).expect("a status"),
+                [(axum::http::header::CONTENT_TYPE, "application/json")],
+                body,
+            )
+        });
+        let listener = tokio::net::TcpListener::bind("127.0.0.1:0")
+            .await
+            .expect("bind");
+        let base = format!("http://{}", listener.local_addr().expect("local addr"));
+        tokio::spawn(async move { axum::serve(listener, app).await });
+        base
+    }
+
+    #[tokio::test]
+    async fn a_whoami_refusal_does_not_quote_the_response_body() {
+        let base =
+            stub_homeserver(502, r#"{"errcode":"M_UNKNOWN","error":"free-form-marker"}"#).await;
+        let e = whoami(&base, "tok").await.expect_err("refused");
+        let message = format!("{e:#}");
+        assert!(message.contains("502"), "{message}");
+        assert!(!message.contains("free-form-marker"), "{message}");
+    }
+
+    #[tokio::test]
+    async fn whoami_reads_both_ids_and_reports_an_unknown_token_as_none() {
+        let base = stub_homeserver(200, r#"{"user_id":"@a:x","device_id":"DEV"}"#).await;
+        let (user, device) = whoami(&base, "tok").await.expect("live").expect("ids");
+        assert_eq!((user.as_str(), device.as_str()), ("@a:x", "DEV"));
+        let base = stub_homeserver(401, r#"{"errcode":"M_UNKNOWN_TOKEN"}"#).await;
+        assert!(whoami(&base, "tok").await.expect("a verdict").is_none());
+    }
 }