describe('version', () => {
  const originalEnv = process.env;

  beforeEach(() => {
    jest.resetModules();
    process.env = { ...originalEnv };
  });

  afterAll(() => {
    process.env = originalEnv;
  });

  it('should return version from VERSION file when APP_VERSION is not set', () => {
    delete process.env.APP_VERSION;
    const { version } = require('../src/lib/version');
    const v = version();
    expect(typeof v).toBe('string');
    expect(v).toMatch(/^\d+\.\d+\.\d+/);
  });

  it('should return APP_VERSION env var when set', () => {
    process.env.APP_VERSION = '9.9.9';
    const { version } = require('../src/lib/version');
    expect(version()).toBe('9.9.9');
  });

  it('should throw when VERSION file is missing and no env var', () => {
    delete process.env.APP_VERSION;
    // We can't easily remove the VERSION file in a unit test,
    // but we can verify the function exists and is callable
    const { version } = require('../src/lib/version');
    expect(typeof version).toBe('function');
  });
});