nEngine/packages/render/test/sync-ws.test.ts

import { afterEach, beforeEach, describe, expect, it, vi } from "vitest";
import { connectWs } from "../src/sync/ws.js";
import type { WsSyncOptions } from "../src/sync/ws.js";
import type { RenderSnapshot, ViewportHandle } from "../src/viewport.js";

/** Minimal WebSocket stand-in with instance tracking for reconnect tests. */
class FakeWebSocket {
  static instances: FakeWebSocket[] = [];
  static OPEN = 1;
  static CONNECTING = 0;
  readyState = FakeWebSocket.CONNECTING;
  onopen: (() => void) | null = null;
  onmessage: ((event: { data: string }) => void) | null = null;
  onclose: (() => void) | null = null;
  onerror: (() => void) | null = null;
  sent: string[] = [];
  constructor(public url: string) {
    FakeWebSocket.instances.push(this);
  }
  send(data: string): void {
    this.sent.push(data);
  }
  close(): void {
    this.readyState = 3; // CLOSED
  }
  open(): void {
    this.readyState = FakeWebSocket.OPEN;
    this.onopen?.();
  }
  receive(frame: unknown): void {
    this.onmessage?.({ data: JSON.stringify(frame) });
  }
  drop(): void {
    this.onclose?.();
  }
}

function fakeViewport(): ViewportHandle {
  return {
    render(_snapshot?: RenderSnapshot): void {},
    tileAt(): { x: number; y: number } | null {
      return null;
    },
    resize(): void {},
    destroy(): void {},
  };
}

function opts(overrides: Partial<WsSyncOptions> = {}): WsSyncOptions {
  return { url: "ws://127.0.0.1:1/mcp", viewport: fakeViewport(), ...overrides };
}

beforeEach(() => {
  vi.useFakeTimers();
  FakeWebSocket.instances = [];
  vi.stubGlobal("WebSocket", FakeWebSocket);
});

afterEach(() => {
  vi.unstubAllGlobals();
  vi.useRealTimers();
});

describe("connectWs sound forwarding (bug-fix round)", () => {
  it("forwards bgm-play and bgm-stop event frames to the sound player", () => {
    const calls: { event: string; payload: unknown }[] = [];
    const sound = { onEvent: (frame: { event: string; payload: unknown }) => calls.push(frame) } as never;
    connectWs(opts({ sound }));
    const socket = FakeWebSocket.instances[0]!;
    socket.open();
    socket.receive({ type: "event", event: "bgm-play", payload: { soundId: "bgm-spring", fadeMs: 1500 } });
    socket.receive({ type: "event", event: "bgm-stop", payload: { fadeMs: 800 } });
    expect(calls).toEqual([
      { type: "event", event: "bgm-play", payload: { soundId: "bgm-spring", fadeMs: 1500 } },
      { type: "event", event: "bgm-stop", payload: { fadeMs: 800 } },
    ]);
  });
});

describe("connectWs reconnect lifecycle (bug-fix round)", () => {
  it("destroy() cancels a queued reconnect — no socket leaks after teardown", () => {
    const handle = connectWs(opts());
    const first = FakeWebSocket.instances[0]!;
    first.open();
    first.drop(); // schedule reconnect
    expect(FakeWebSocket.instances).toHaveLength(1);
    handle.destroy();
    vi.advanceTimersByTime(600);
    expect(FakeWebSocket.instances).toHaveLength(1); // no second socket created
  });

  it("reconnects while alive and keeps working after a reconnect", () => {
    const handle = connectWs(opts());
    const first = FakeWebSocket.instances[0]!;
    first.open();
    first.drop();
    vi.advanceTimersByTime(500);
    expect(FakeWebSocket.instances).toHaveLength(2);
    const second = FakeWebSocket.instances[1]!;
    second.open();
    second.receive({ type: "event", event: "bgm-stop", payload: {} });
    handle.destroy();
  });
});