test(20-01): add failing tests for tag service and route

- Tag service tests: empty array, alphabetical ordering, id+name projection
- Tag route tests: GET /api/tags returns 200, correct tag objects

tests/routes/tags.test.ts

@@ -0,0 +1,53 @@
+import { beforeEach, describe, expect, it } from "bun:test";
+import { Hono } from "hono";
+import { tags } from "../../src/db/schema.ts";
+import { tagRoutes } from "../../src/server/routes/tags.ts";
+import { createTestDb } from "../helpers/db.ts";
+
+function createTestApp(db: any) {
+	const app = new Hono();
+
+	app.use("*", async (c, next) => {
+		c.set("db", db);
+		await next();
+	});
+
+	app.route("/api/tags", tagRoutes);
+	return app;
+}
+
+describe("Tag Routes", () => {
+	let app: Hono;
+	let db: Awaited<ReturnType<typeof createTestDb>>["db"];
+
+	beforeEach(async () => {
+		const testDb = await createTestDb();
+		db = testDb.db;
+		app = createTestApp(db);
+	});
+
+	describe("GET /api/tags", () => {
+		it("returns 200 with empty array when no tags", async () => {
+			const res = await app.request("/api/tags");
+			expect(res.status).toBe(200);
+
+			const body = await res.json();
+			expect(body).toEqual([]);
+		});
+
+		it("returns 200 with tag objects after seeding", async () => {
+			await db.insert(tags).values([
+				{ name: "bikepacking" },
+				{ name: "ultralight" },
+			]);
+
+			const res = await app.request("/api/tags");
+			expect(res.status).toBe(200);
+
+			const body = await res.json();
+			expect(body).toHaveLength(2);
+			expect(body[0]).toHaveProperty("id");
+			expect(body[0]).toHaveProperty("name");
+		});
+	});
+});