Address PR feedback: backtick formatting in changelog, dynamic describe name, add snapshot tests

Agent-Logs-Url: https://github.com/microsoft/rushstack/sessions/f33fe415-7fc0-4905-8330-774013ebbe50

Co-authored-by: dmichon-msft <26827560+dmichon-msft@users.noreply.github.com>

Author: Copilot

common/changes/@rushstack/lookup-by-path/enhance-lookup-by-path-json-methods_2026-04-07-22-32.json

@@ -1,7 +1,7 @@
 {
   "changes": [
     {
-      "comment": "Add toJson/fromJson methods to LookupByPath for serialization/deserialization",
+      "comment": "Add `toJson`/`fromJson` methods to `LookupByPath` for serialization/deserialization",
       "type": "minor",
       "packageName": "@rushstack/lookup-by-path"
     }

libraries/lookup-by-path/src/test/LookupByPath.test.ts

@@ -675,7 +675,7 @@ describe(LookupByPath.prototype.groupByChild.name, () => {
   });
 });
 
-describe('toJson and fromJson', () => {
+describe(`${LookupByPath.prototype.toJson.name} and ${LookupByPath.fromJson.name}`, () => {
   it('round-trips an empty trie', () => {
     const original = new LookupByPath<number>();
     const json: ILookupByPathJson<number> = original.toJson((v) => v);
@@ -702,6 +702,31 @@ describe('toJson and fromJson', () => {
     expect(restored.get('missing')).toEqual(undefined);
   });
 
+  it('snapshot: serialized JSON for a simple tree', () => {
+    const original = new LookupByPath<number>([
+      ['foo', 1],
+      ['foo/bar', 2],
+      ['baz', 3]
+    ]);
+
+    const json: ILookupByPathJson<number> = original.toJson((v) => v);
+    expect(json).toMatchSnapshot();
+  });
+
+  it('snapshot: serialized JSON with intermediate nodes and custom delimiter', () => {
+    const original = new LookupByPath<string>(
+      [
+        ['a,b,c', 'deep'],
+        ['a,b', 'mid'],
+        ['x', 'top']
+      ],
+      ','
+    );
+
+    const json: ILookupByPathJson<string> = original.toJson((v) => v);
+    expect(json).toMatchSnapshot();
+  });
+
   it('round-trips with string values', () => {
     const original = new LookupByPath<string>([
       ['a', 'alpha'],

libraries/lookup-by-path/src/test/__snapshots__/LookupByPath.test.ts.snap

@@ -0,0 +1,57 @@
+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`toJson and fromJson snapshot: serialized JSON for a simple tree 1`] = `
+Object {
+  "delimiter": "/",
+  "tree": Object {
+    "children": Object {
+      "baz": Object {
+        "valueIndex": 2,
+      },
+      "foo": Object {
+        "children": Object {
+          "bar": Object {
+            "valueIndex": 1,
+          },
+        },
+        "valueIndex": 0,
+      },
+    },
+  },
+  "values": Array [
+    1,
+    2,
+    3,
+  ],
+}
+`;
+
+exports[`toJson and fromJson snapshot: serialized JSON with intermediate nodes and custom delimiter 1`] = `
+Object {
+  "delimiter": ",",
+  "tree": Object {
+    "children": Object {
+      "a": Object {
+        "children": Object {
+          "b": Object {
+            "children": Object {
+              "c": Object {
+                "valueIndex": 1,
+              },
+            },
+            "valueIndex": 0,
+          },
+        },
+      },
+      "x": Object {
+        "valueIndex": 2,
+      },
+    },
+  },
+  "values": Array [
+    "mid",
+    "deep",
+    "top",
+  ],
+}
+`;