我想测试一个方法，它返回Promise.AllSettled()的结果，并调用另一个返回承诺的函数。
我将问题简化为以下测试代码:
describe('Promise tests', () => {
it('should reject directly', async () => {
const f = jest.fn().mockRejectedValue(new Error('foo'));
const p = async () => await f();
// works
await expect(p).rejects.toThrow('foo');
});
it('should reject with allSettled', async () => {
const f = jest.fn().mockRejectedValue(new Error('foo'));
const p = async () => await f();
const results = await Promise.allSettled([p]);
expect(results[0].status).toBe('rejected'); // fulfilled - but why?
expect(results[0].reason).toBe('foo');
});
});
为什么第二个案例没有收到被拒绝的承诺？
你就快到了。promise.AllSettlement期望接收一个承诺数组，而不是返回承诺的函数数组，这实际上是常量P所做的。
只需调用p()即可解决问题:
describe('Promise tests', () => {
it('should reject directly', async () => {
const f = jest.fn().mockRejectedValue(new Error('foo'));
const p = async () => await f();
// works
await expect(p()).rejects.toThrow('foo');
});
it('should reject with allSettled', async () => {
const f = jest.fn().mockRejectedValue(new Error('foo'));
const p = async () => await f();
const results = await Promise.allSettled([p()]);
expect(results[0].status).toBe('rejected'); // fulfilled - but why?
expect(results[0].reason).toBe('foo');
});
});
顺便说一句:我的短绒抱怨不必要的等待:-）
