test: assert うしろのこ and ushironoko stay unified

Guard against reintroducing a separate ushironoko speaker entry
that would split DirectoryView aggregation again.

Co-authored-by: Oyama Michinoku <0910yama@gmail.com>

Author: cursoragent

src/data/index.test.ts

@@ -1,5 +1,6 @@
 import { describe, expect, it } from "vite-plus/test";
 import { YEARS } from "../../types";
+import { getSpeakerNames, getSpeakerTalks } from "../composables/speaker";
 import { getAllSpeakersWithYear, getSpeakersByYear } from "./index";
 
 describe("speaker data accessors", () => {
@@ -16,4 +17,13 @@ describe("speaker data accessors", () => {
     expect(speakers.length).toBeGreaterThan(0);
     expect(speakers.every((speaker) => YEARS.includes(speaker.year))).toBe(true);
   });
+
+  it("うしろのこは ushironoko と同一人物として集約される", () => {
+    const talks = getSpeakerTalks("うしろのこ");
+    const years = talks.map((talk) => talk.year);
+
+    expect(years).toEqual(expect.arrayContaining(["2022", "2023", "2026"]));
+    expect(getSpeakerNames()).not.toContain("ushironoko");
+    expect(getSpeakerTalks("ushironoko")).toEqual([]);
+  });
 });