add tests for announcement file format

frontend/app/components/Domain/Announcement/Announcements/announcements.test.ts

@@ -0,0 +1,37 @@
+import { describe, test, expect } from "vitest";
+
+const announcementFiles = import.meta.glob<{ default: unknown }>(
+  "~/components/Domain/Announcement/Announcements/*.vue",
+);
+
+// Expected format: YYYY-MM-DD_N_slug  e.g. 2026-03-27_1_welcome
+const FILE_FORMAT = /^\d{4}-\d{2}-\d{2}_\d+_.+$/;
+
+describe("Announcement files", () => {
+  const filenames = Object.keys(announcementFiles).map(path =>
+    path.split("/").at(-1)!.replace(".vue", ""),
+  );
+
+  test("directory is not empty", () => {
+    expect(filenames.length).toBeGreaterThan(0);
+  });
+
+  test("all filenames match YYYY-MM-DD_N_slug format", () => {
+    for (const name of filenames) {
+      expect(name, `"${name}" does not match the expected format`).toMatch(FILE_FORMAT);
+    }
+  });
+
+  test("all date prefixes are valid dates", () => {
+    for (const name of filenames) {
+      const datePart = name.split("_", 1)[0]!;
+      const date = new Date(datePart);
+      expect(isNaN(date.getTime()), `"${name}" has an invalid date prefix "${datePart}"`).toBe(false);
+    }
+  });
+
+  test("all filenames are unique", () => {
+    const unique = new Set(filenames);
+    expect(unique.size).toBe(filenames.length);
+  });
+});

frontend/vitest.config.js

@@ -1,6 +1,8 @@
 import path from "path";
+import vue from "@vitejs/plugin-vue";
 
 export default {
+  plugins: [vue()],
   test: {
     globals: true,
     environment: "jsdom",