Harden gameplay timing and map loading

tests/client-api.test.ts

@@ -0,0 +1,46 @@
+import { test } from "node:test";
+import assert from "node:assert/strict";
+import { api } from "../lib/client-api";
+
+test("API sends explicit falsy JSON bodies and prevents cached private responses", async (t) => {
+  const fetch = t.mock.method(
+    globalThis,
+    "fetch",
+    async (_url: unknown, options: RequestInit) => {
+      assert.equal(options.method, "POST");
+      assert.equal(options.body, "false");
+      assert.equal(options.cache, "no-store");
+      return Response.json({ ok: true });
+    },
+  );
+  assert.deepEqual(await api("test", false), { ok: true });
+  assert.equal(fetch.mock.callCount(), 1);
+});
+
+test("API explains HTML gateway failures, JSON errors, and empty error responses", async (t) => {
+  const fetch = t.mock.method(
+    globalThis,
+    "fetch",
+    async () => new Response("Bad gateway", { status: 502 }),
+  );
+  await assert.rejects(api("test"), /unreadable response/);
+  fetch.mock.mockImplementation(async () =>
+    Response.json({ error: "Map unavailable" }, { status: 404 }),
+  );
+  await assert.rejects(api("test"), /Map unavailable/);
+  fetch.mock.mockImplementation(async () =>
+    Response.json(null, { status: 503 }),
+  );
+  await assert.rejects(api("test"), /Request failed/);
+});
+
+test("API reports timeouts and offline connections with a recovery action", async (t) => {
+  const fetch = t.mock.method(globalThis, "fetch", async () => {
+    throw new DOMException("timeout", "TimeoutError");
+  });
+  await assert.rejects(api("test"), /timed out.*Reconnect/);
+  fetch.mock.mockImplementation(async () => {
+    throw new TypeError("Failed to fetch");
+  });
+  await assert.rejects(api("test"), /Check your connection/);
+});