pixi-demo/tests/kernel/scene-manager-rollback.test.ts

import { beforeEach, describe, expect, it, vi } from "vitest";
import { SceneType } from "@/enums/SceneType";
import type { IBaseScene } from "@/scene/types";

class MockContainer {
  visible = true;
  label = "";
  _isHolderLast?: boolean;
  children: MockContainer[] = [];
  destroyed = false;

  addChild(child: MockContainer): MockContainer {
    this.children.push(child);
    return child;
  }

  removeChild(child: MockContainer): MockContainer {
    this.children = this.children.filter((item) => item !== child);
    return child;
  }

  destroy(): void {
    this.destroyed = true;
  }
}

vi.mock("pixi.js", () => ({
  Container: MockContainer,
}));

vi.mock("@/core/Game", () => {
  class MockGame {
    private static instance: MockGame;
    readonly stage = new MockContainer();

    static getInstance(): MockGame {
      if (!MockGame.instance) {
        MockGame.instance = new MockGame();
      }
      return MockGame.instance;
    }
  }

  return {
    default: MockGame,
  };
});

function createScene(
  name: string,
  type: SceneType = SceneType.Normal,
  onLoad?: () => Promise<void> | void
): IBaseScene {
  const stage = new MockContainer();
  stage.label = name;

  return {
    name,
    type,
    stage: stage as never,
    _assetsLoaded: true,
    _layoutDone: true,
    changeScene: () => {},
    onLoad,
    onUnLoad: async () => {},
    loadBundle: async () => {},
    unLoadBundle: async () => {},
    layout: async () => {},
  };
}

describe("SceneManager rollback consistency", () => {
  beforeEach(async () => {
    vi.resetModules();
    const module = await import("@/scene/SceneManager");
    (module.default as unknown as { instance?: unknown }).instance = undefined;
  });

  it("restores previous scene visibility and mount when transition fails", async () => {
    const module = await import("@/scene/SceneManager");
    const SceneManager = module.default;

    const manager = SceneManager.getInstance();
    const previous = createScene("previous");
    const target = createScene("target", SceneType.Normal, async () => {
      throw new Error("target onLoad failed");
    });

    manager.registerScene(previous);
    manager.registerScene(target);
    await manager.initScene("previous");

    expect(previous.stage.visible).toBe(true);
    expect(manager.currentScene).toBe(previous);

    await expect(
      manager.changeScene("target", { isHolderLast: true })
    ).rejects.toThrowError("target onLoad failed");

    expect(manager.currentScene).toBe(previous);
    expect(previous.stage.visible).toBe(true);
    expect(manager["game"].stage.children.includes(previous.stage as never)).toBe(
      true
    );
    expect(manager["game"].stage.children.includes(target.stage as never)).toBe(
      false
    );
  });
});