我们使用jest来测试我们的API,并且有相当复杂的场景。我们使用 beforeAll
函数来设置每个测试的通用辅助变量,有时也会设置租户分离,在其他情况下,我们会使用 beforeEach
函数来设置测试的租户分离,以及一些测试租户的默认配置,......。
例如,一个测试可以像这样(如你所见,我们使用TypeScript来编写测试,以防万一)。
let apiClient: ApiClient;
let tenantId: string;
beforeAll(async () => {
apiClient = await getClientWithCredentials();
});
beforeEach(async () => {
tenantId = await createNewTestTenant();
});
describe('describing complex test scenario', () => {
it('should have some initial state', async () => {
await checkState(tenantId);
});
it('should have some state after performing op1', async () =>{
await op1(tenantId);
await checkStateAfterOp1(tenantId);
});
it('should have some state after performing op2', async () =>{
await op2(tenantId);
await checkStateAfterOp2(tenantId);
});
it('should have some state after performing op1 and op2', async () =>{
await op1(tenantId);
await op2(tenantId);
await checkStateAfterOp1AndOp2(tenantId);
});
it('the order of op1 and op2 should not matter', async () =>{
await op2(tenantId);
await op1(tenantId);
await checkStateAfterOp1AndOp2(tenantId);
});
});
describe('another similar complex scenario', () => {
// ... you see where this is going
});
问题是,什么是共享这些变量的最佳方式?beforeAll
和 beforeEach
? - 上述测试如果在执行 --runInBand
选项,其中 "......在当前进程中串行运行所有测试......"
但当并行执行时,它开始很随机地失败,主要指的是 tenantId
是未定义的。考虑到这些测试是大约200个类似测试的一部分,串行时全部通过。在并行方面,则取决于机器。8核16线程的构建代理只有50-60%的测试通过。我的同事用四核CPU的测试通过率为80%,而我用双核CPU的测试有时只有1-2次失败,有时有10次。所以很明显,这取决于并行的数量。
我发现有2个GitHub的问题,人们在那里提到可以使用 this
来共享上下文(现在不行了),或者把所有的东西都封装在 describe
:
所以我尝试了一个非常天真的方法。
describe('tests', () => {
let apiClient: ApiClient;
let tenantId: string;
beforeAll(async () => {
apiClient = await getClientWithCredentials();
});
beforeEach(async () => {
tenantId = await createNewTestTenant();
});
describe('describing complex test scenario', () => {
it('should have some initial state', async () => {
await checkState(tenantId);
});
it('should have some state after performing op1', async () =>{
await op1(tenantId);
await checkStateAfterOp1(tenantId);
});
it('should have some state after performing op2', async () =>{
await op2(tenantId);
await checkStateAfterOp2(tenantId);
});
it('should have some state after performing op1 and op2', async () =>{
await op1(tenantId);
await op2(tenantId);
await checkStateAfterOp1AndOp2(tenantId);
});
it('the order of op1 and op2 should not matter', async () =>{
await op2(tenantId);
await op1(tenantId);
await checkStateAfterOp1AndOp2(tenantId);
});
});
describe('another similar complex scenario', () => {
// ... you see where this is going
});
});
但这似乎没有任何效果. 我真的很想并行运行测试, 但我在文档中找不到任何有关的内容. 也许我不知道我应该找什么?
这对你有用吗?
describe('tests', () => {
let apiClient: ApiClient;
let tenantIds: {id: string, used: boolean}[];
const findUnusedTenantId = () => {
const tenant = tenantIds.find(a => !a.used);
tenant.used = true;
return tenant.id
}
beforeAll(async () => {
apiClient = await getClientWithCredentials();
});
beforeEach(async () => {
const id = await createNewTestTenant();
tenantIds.push({id, used: false})
});
describe('describing complex test scenario', () => {
let tenantId: string
it('should have some initial state', async () => {
tenantId = fineUnusedTenantId();
await checkState(tenantId);
});
it('should have some state after performing op1', async () =>{
await op1(tenantId);
await checkStateAfterOp1(tenantId);
});
// ...
});
describe('next scenario', () => {
let tenantId: string
it('first test', async () => {
tenantId = fineUnusedTenantId();
await checkState(tenantId);
});
你可能需要一个AfterAll钩子来清理数据库。