function assert(value, message) {
  if (!value) {
    throw new Error(message);
  }
}

const expect = (actual) => ({
  toBe: (expected) => {
    assert(actual === expected, `期望 ${actual} 等于 ${expected}`);
  },
  notToBe: (unexpected) => {
    assert(actual !== unexpected, `期望 ${actual} 不等于 ${unexpected}`);
  },
  toBeTruthy: () => {
    assert(Boolean(actual), `${actual} 应该为真`);
  },
  toBeFalsy: () => {
    assert(!Boolean(actual), `${actual} 应该为假`);
  }
});

const tests = [];

function test(name, fn) {
  tests.push({ name, fn, type: 'test' });
}

function describe(groupName, fn) {
  console.log(`\n【测试组】${groupName}`);
  fn();
}

function runTests() {
  let passed = 0;
  let failed = 0;

  tests.forEach(({ name, fn }) => {
    try {
      fn();
      console.log(`✅ ${name}`);
      passed++;
    } catch (e) {
      console.log(`❌ ${name} - ${e.message}`);
      failed++;
    }
  });

  console.log(`\n? 测试完成：${passed} 通过，${failed} 失败`);
}

describe('数学运算测试', () => {
  test('2 + 2 等于 4', () => {
    expect(2 + 2).toBe(4);
  });

  test('字符串相等', () => {
    expect('hello').toBe('hello');
  });

  test('布尔值为真', () => {
    expect(true).toBeTruthy();
  });
});

runTests();