test: add golden fixtures for skeleton output and drill-down refmap

Adds two committed JSON fixtures under tests/fixtures/ plus matching
unit tests that build the same input trees, run them through
allocate_refs / run_from_ref, and assert the produced ref ids,
parent-child layout, and root_ref tagging match the golden expectations.
Locks in the JSON shape so future serialization changes have to be
deliberate.

crates/core/src/snapshot.rs

@@ -385,4 +385,61 @@ mod tests {
         assert_eq!(result.children.len(), 1);
         assert_eq!(result.children[0].children_count, Some(10));
     }
+
+    #[test]
+    fn test_skeleton_fixture_matches_golden() {
+        let golden = include_str!("../../../tests/fixtures/skeleton-tree.json");
+        let golden_value: serde_json::Value = serde_json::from_str(golden).unwrap();
+
+        let mut sidebar = node("group");
+        sidebar.name = Some("Sidebar".into());
+        sidebar.children_count = Some(26);
+
+        let mut described = node("group");
+        described.description = Some("Channels and direct messages".into());
+        described.children_count = Some(12);
+
+        let mut send = node("button");
+        send.name = Some("Send".into());
+        let mut msg = node("textfield");
+        msg.name = Some("Message".into());
+        let mut content = node("group");
+        content.name = Some("Content".into());
+        content.children = vec![send, msg];
+
+        let mut root = node("window");
+        root.name = Some("Test Window".into());
+        root.children = vec![sidebar, described, content];
+
+        let mut refmap = RefMap::new();
+        let result = allocate_refs(root, &mut refmap, false, false, false, 42, Some("Fixture"));
+
+        assert_eq!(refmap.len(), 4, "should allocate 4 refs total");
+        let result_value = serde_json::to_value(&result).unwrap();
+
+        assert_eq!(result_value["role"], golden_value["role"]);
+        assert_eq!(result_value["name"], golden_value["name"]);
+        assert_eq!(
+            result_value["children"][0]["ref_id"], golden_value["children"][0]["ref_id"],
+            "named skeleton anchor should be @e1"
+        );
+        assert_eq!(
+            result_value["children"][0]["children_count"],
+            golden_value["children"][0]["children_count"]
+        );
+        assert_eq!(
+            result_value["children"][1]["ref_id"], golden_value["children"][1]["ref_id"],
+            "described skeleton anchor should be @e2"
+        );
+        assert_eq!(
+            result_value["children"][2]["children"][0]["ref_id"],
+            golden_value["children"][2]["children"][0]["ref_id"],
+            "interactive button should be @e3"
+        );
+        assert_eq!(
+            result_value["children"][2]["children"][1]["ref_id"],
+            golden_value["children"][2]["children"][1]["ref_id"],
+            "interactive textfield should be @e4"
+        );
+    }
 }

crates/core/src/snapshot_ref.rs

@@ -315,6 +315,64 @@ mod tests {
         assert_eq!(entry_two.root_ref.as_deref(), Some("@e2"));
     }
 
+    #[test]
+    fn test_drilldown_refmap_matches_golden_fixture() {
+        let golden = include_str!("../../../tests/fixtures/drilldown-refmap.json");
+        let golden_value: serde_json::Value = serde_json::from_str(golden).unwrap();
+        let expected_total = golden_value["expected_total"].as_u64().unwrap() as usize;
+
+        let _guard = HomeGuard::new();
+        let mut seed = RefMap::new();
+        seed.allocate(ref_entry_from_node(
+            &named("group", "Sidebar"),
+            42,
+            Some("Fixture"),
+            None,
+        ));
+        seed.allocate(ref_entry_from_node(
+            &named("group", "Toolbar"),
+            42,
+            Some("Fixture"),
+            None,
+        ));
+        seed.save().unwrap();
+
+        let mut sidebar_subtree = named("outline", "Sidebar");
+        sidebar_subtree.children =
+            vec![named("treeitem", "Recents"), named("treeitem", "Documents")];
+        let adapter = StubAdapter::new(sidebar_subtree);
+        let _ = run_from_ref(&adapter, &drill_opts(), "@e1").unwrap();
+
+        let toolbar_subtree = named("button", "Back");
+        let adapter = StubAdapter::new(toolbar_subtree);
+        let _ = run_from_ref(&adapter, &drill_opts(), "@e2").unwrap();
+
+        let on_disk = RefMap::load().unwrap();
+        assert_eq!(
+            on_disk.len(),
+            expected_total,
+            "merged refmap should match golden fixture's expected_total"
+        );
+
+        for anchor in golden_value["skeleton_anchors"].as_array().unwrap() {
+            let id = anchor["ref_id"].as_str().unwrap();
+            let entry = on_disk.get(id).unwrap_or_else(|| panic!("missing {id}"));
+            assert_eq!(entry.role, anchor["role"].as_str().unwrap());
+            assert_eq!(entry.name.as_deref(), anchor["name"].as_str());
+            assert!(
+                entry.root_ref.is_none(),
+                "skeleton {id} must have null root_ref"
+            );
+        }
+
+        for drill in golden_value["drilled_from_e1"].as_array().unwrap() {
+            let id = drill["ref_id"].as_str().unwrap();
+            if let Some(entry) = on_disk.get(id) {
+                assert_eq!(entry.root_ref.as_deref(), Some("@e1"));
+            }
+        }
+    }
+
     #[test]
     fn test_run_from_ref_empty_subtree() {
         let _guard = HomeGuard::new();

tests/fixtures/drilldown-refmap.json

@@ -0,0 +1,44 @@
+{
+  "skeleton_anchors": [
+    {
+      "ref_id": "@e1",
+      "pid": 42,
+      "role": "group",
+      "name": "Sidebar",
+      "root_ref": null
+    },
+    {
+      "ref_id": "@e2",
+      "pid": 42,
+      "role": "group",
+      "name": "Toolbar",
+      "root_ref": null
+    }
+  ],
+  "drilled_from_e1": [
+    {
+      "ref_id": "@e3",
+      "pid": 42,
+      "role": "treeitem",
+      "name": "Recents",
+      "root_ref": "@e1"
+    },
+    {
+      "ref_id": "@e4",
+      "pid": 42,
+      "role": "treeitem",
+      "name": "Documents",
+      "root_ref": "@e1"
+    }
+  ],
+  "drilled_from_e2": [
+    {
+      "ref_id": "@e5",
+      "pid": 42,
+      "role": "button",
+      "name": "Back",
+      "root_ref": "@e2"
+    }
+  ],
+  "expected_total": 5
+}

tests/fixtures/skeleton-tree.json

@@ -0,0 +1,35 @@
+{
+  "ref_id": null,
+  "role": "window",
+  "name": "Test Window",
+  "children": [
+    {
+      "ref_id": "@e1",
+      "role": "group",
+      "name": "Sidebar",
+      "children_count": 26
+    },
+    {
+      "ref_id": "@e2",
+      "role": "group",
+      "description": "Channels and direct messages",
+      "children_count": 12
+    },
+    {
+      "role": "group",
+      "name": "Content",
+      "children": [
+        {
+          "ref_id": "@e3",
+          "role": "button",
+          "name": "Send"
+        },
+        {
+          "ref_id": "@e4",
+          "role": "textfield",
+          "name": "Message"
+        }
+      ]
+    }
+  ]
+}