其实就是一个同步代码执行的程序顺便触发了对应的钩子函数;
beforeAll(() => console.log('1 - beforeAll'));afterAll(() => console.log('1 - afterAll'));beforeEach(() => console.log('1 - beforeEach'));afterEach(() => console.log('1 - afterEach'));test('', () => console.log('1 - test'));describe('Scoped / Nested block', () => { beforeAll(() => console.log('2 - beforeAll')); afterAll(() => console.log('2 - afterAll')); beforeEach(() => console.log('2 - beforeEach')); afterEach(() => console.log('2 - afterEach')); test('', () => console.log('2 - test'));});// 1 - beforeAll// 1 - beforeEach// 1 - test// 1 - afterEach// 2 - beforeAll// 1 - beforeEach// 2 - beforeEach// 2 - test// 2 - afterEach// 1 - afterEach// 2 - afterAll// 1 - afterAll