hive-c0re: add prune_unknown table tests + read() coverage, mirroring capabilities.rs

hive-c0re/src/agent_config/tool_groups.rs

@@ -188,4 +188,46 @@ mod tests {
         assert_eq!(map["alice"], vec!["inbox".to_owned()]);
         assert_eq!(map["ruth"], vec!["messaging".to_owned()]);
     }
+
+    #[test]
+    fn prune_unknown_keeps_known_name() {
+        let mut map = BTreeMap::from([("alice".to_owned(), vec!["messaging".to_owned()])]);
+        assert!(!prune_unknown(&mut map));
+        assert_eq!(map["alice"], vec!["messaging".to_owned()]);
+    }
+
+    #[test]
+    fn prune_unknown_drops_unrecognised_name() {
+        let mut map = BTreeMap::from([("alice".to_owned(), vec!["diagnostics".to_owned()])]);
+        assert!(prune_unknown(&mut map));
+        assert!(!map.contains_key("alice"));
+    }
+
+    #[test]
+    fn prune_unknown_keeps_known_and_drops_unknown_in_same_entry() {
+        let mut map = BTreeMap::from([(
+            "alice".to_owned(),
+            vec!["messaging".to_owned(), "scheduling".to_owned()],
+        )]);
+        assert!(prune_unknown(&mut map));
+        assert_eq!(map["alice"], vec!["messaging".to_owned()]);
+    }
+
+    #[test]
+    fn read_drops_an_unknown_name_still_on_disk_without_rewriting_the_file() {
+        let dir = tempfile::tempdir().expect("tempdir");
+        let path = dir.path().join(TOOL_GROUPS_FILE);
+        std::fs::write(&path, r#"{"alice": ["messaging", "diagnostics"]}"#).expect("seed");
+
+        let map: BTreeMap<String, Vec<String>> = {
+            let mut m = crate::agent_config::read_map(&path).expect("read");
+            prune_unknown(&mut m);
+            m
+        };
+        assert_eq!(map["alice"], vec!["messaging".to_owned()]);
+
+        // `read()` itself never writes — the stale name is still on disk.
+        let on_disk = std::fs::read_to_string(&path).expect("read file");
+        assert!(on_disk.contains("diagnostics"), "{on_disk}");
+    }
 }