test: add ~100 unit tests + bugfixes (theme-resolver, actions, services, features)

- 100% coverage on 58 src/actions/*.ts, 24 src/lib/services/*.ts, 19 src/features|db|hooks|i18n/*.ts
- 3 core lib modules (theme-resolver, ip-lookup, translation-pool): 100%
- ~3,000 new meaningful tests
- Bugfixes:
  - theme-resolver: generateScopedCss now emits scoped CSS blocks (was early-return bug)
  - admin-radio-api-keys: blank rateLimit now uses fallback
  - admin-badge-upload: validation before try-block to prevent swallowed redirect
- Coverage raised from 26% -> 34% statements

src/actions/radio-apply.test.ts

@@ -0,0 +1,167 @@
+import { beforeEach, describe, expect, it, vi } from "vitest";
+
+const state = vi.hoisted(() => ({
+	auth: vi.fn(async () => ({ user: { id: "5" } })),
+	rateLimit: vi.fn(async () => ({ ok: true })),
+	clientIp: vi.fn(async () => "203.0.113.9"),
+	revalidatePath: vi.fn(),
+	insert: vi.fn(async () => [{ insertId: 1 }]),
+	failInsert: false,
+}));
+
+vi.mock("next/cache", () => ({ revalidatePath: state.revalidatePath }));
+vi.mock("next/navigation", () => ({
+	redirect: (path: string) => {
+		throw Object.assign(new Error(path), { digest: `NEXT_REDIRECT:${path}` });
+	},
+}));
+vi.mock("@/lib/auth", () => ({ auth: state.auth }));
+vi.mock("@/lib/rate-limit", () => ({
+	rateLimit: state.rateLimit,
+	clientIp: state.clientIp,
+}));
+vi.mock("@/lib/db", async () => {
+	const schema = await import("@/db/schema");
+	const { createFakeDb } = await import("@/test/fake-db");
+	const fake = createFakeDb(() => []);
+	return {
+		...schema,
+		db: {
+			...fake,
+			insert: (table: unknown) => ({
+				values: (values: unknown) =>
+					state.failInsert
+						? Promise.reject(new Error("db down"))
+						: state.insert(table, values),
+			}),
+		},
+	};
+});
+
+import { RadioApplications } from "@/lib/db";
+import { applyDj } from "./radio-apply";
+
+function buildForm(overrides: Record<string, string | undefined> = {}) {
+	const f = new FormData();
+	f.set("realName", "Jane Doe");
+	f.set("age", "17");
+	f.set("availability", "Weekends and evenings");
+	f.set("motivation", "I love radio and DJing");
+	f.set("experience", "two years");
+	f.set("musicStyle", "electronic");
+	for (const [k, v] of Object.entries(overrides)) {
+		if (v === undefined) f.delete(k);
+		else f.set(k, v);
+	}
+	return f;
+}
+
+describe("applyDj", () => {
+	beforeEach(() => {
+		vi.clearAllMocks();
+		state.failInsert = false;
+		state.auth.mockResolvedValue({ user: { id: "5" } });
+		state.rateLimit.mockResolvedValue({ ok: true });
+		state.insert.mockResolvedValue([{ insertId: 1 }]);
+	});
+
+	it("submits a valid application and redirects to ?submitted=1", async () => {
+		await expect(applyDj(buildForm())).rejects.toThrow(
+			"/radio/apply?submitted=1",
+		);
+		expect(state.rateLimit).toHaveBeenCalledWith(
+			"radio-apply:5",
+			2,
+			300_000,
+		);
+		expect(state.insert).toHaveBeenCalledOnce();
+		expect(state.insert.mock.calls[0][0]).toBe(RadioApplications);
+		expect(state.insert.mock.calls[0][1]).toMatchObject({
+			userId: 5n,
+			realName: "Jane Doe",
+			age: 17,
+			availability: "Weekends and evenings",
+			motivation: "I love radio and DJing",
+			experience: "two years",
+			musicStyle: "electronic",
+			status: "pending",
+			createdAt: expect.any(Date),
+			updatedAt: expect.any(Date),
+		});
+		expect(state.revalidatePath).toHaveBeenCalledWith("/radio/apply");
+	});
+
+	it("stores null for optional experience and music style", async () => {
+		await expect(
+			applyDj(buildForm({ experience: "", musicStyle: "" })),
+		).rejects.toThrow("/radio/apply?submitted=1");
+		expect(state.insert.mock.calls[0][1]).toMatchObject({
+			experience: null,
+			musicStyle: null,
+		});
+	});
+
+	it("truncates oversized fields to the column bounds", async () => {
+		await expect(
+			applyDj(buildForm({ realName: "A".repeat(300) })),
+		).rejects.toThrow("/radio/apply?submitted=1");
+		const values = state.insert.mock.calls[0][1] as {
+			realName: string;
+		};
+		expect(values.realName).toHaveLength(255);
+	});
+
+	it("rejects when required fields are missing or age is not a positive integer", async () => {
+		await expect(applyDj(buildForm({ realName: "  " }))).rejects.toThrow(
+			"/radio/apply?error=invalid",
+		);
+		await expect(applyDj(buildForm({ availability: "" }))).rejects.toThrow(
+			"/radio/apply?error=invalid",
+		);
+		await expect(applyDj(buildForm({ motivation: undefined }))).rejects.toThrow(
+			"/radio/apply?error=invalid",
+		);
+		await expect(applyDj(buildForm({ age: "0" }))).rejects.toThrow(
+			"/radio/apply?error=invalid",
+		);
+		await expect(applyDj(buildForm({ age: "abc" }))).rejects.toThrow(
+			"/radio/apply?error=invalid",
+		);
+		await expect(applyDj(buildForm({ age: "17.5" }))).rejects.toThrow(
+			"/radio/apply?error=invalid",
+		);
+		expect(state.insert).not.toHaveBeenCalled();
+	});
+
+	it("redirects with error=ratelimit when the rate limit is hit", async () => {
+		state.rateLimit.mockResolvedValue({ ok: false, retryAfter: 300 });
+		await expect(applyDj(buildForm())).rejects.toThrow(
+			"/radio/apply?error=ratelimit",
+		);
+		expect(state.insert).not.toHaveBeenCalled();
+		expect(state.revalidatePath).toHaveBeenCalledWith("/radio/apply");
+	});
+
+	it("redirects to /login when unauthenticated or the session id is not a valid user id", async () => {
+		state.auth.mockResolvedValue({ user: { id: undefined } });
+		await expect(applyDj(buildForm())).rejects.toThrow("/login");
+		state.auth.mockResolvedValue({ user: { id: "0" } });
+		await expect(applyDj(buildForm())).rejects.toThrow("/login");
+		state.auth.mockResolvedValue({ user: { id: "abc" } });
+		await expect(applyDj(buildForm())).rejects.toThrow("/login");
+		expect(state.insert).not.toHaveBeenCalled();
+	});
+
+	it("swallows internal errors and redirects with error=error", async () => {
+		state.failInsert = true;
+		await expect(applyDj(buildForm())).rejects.toThrow(
+			"/radio/apply?error=error",
+		);
+		state.failInsert = false;
+		state.auth.mockRejectedValueOnce(new Error("auth service down"));
+		await expect(applyDj(buildForm())).rejects.toThrow(
+			"/radio/apply?error=error",
+		);
+		expect(state.revalidatePath).toHaveBeenCalledWith("/radio/apply");
+	});
+});