Question

我们使用jest来测试我们的API并且具有非常复杂的场景。我们使用beforeAll函数为每个测试设置一般辅助变量，有时用于设置租户分离，在其他情况下，我们使用beforeEach函数为测试设置租户分离，有些默认测试租户的配置，......

例如，测试可能会像这样（你可以看到，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，分享由beforeAll和beforeEach初始化的变量的最佳方法是什么？ - 如果使用--runInBand选项执行上述测试，“...在当前流程中按顺序运行所有测试......”

但是当并行执行时，它开始随机失败，主要是指tenantId未定义。鉴于这些测试是约200个类似测试的一部分，所有测试都通过。并行取决于机器。具有8个核心/ 16个线程的构建代理只有50-60％的通过测试。我的四核CPU的同事有80％的通过测试，对于我来说，双核CPU有时只有1-2次测试失败，有时只有10次。显然这取决于并行度。

我发现了2个GitHub问题，其中人们提到了使用this分享上下文（不再起作用）或将所有内容封装在describe中的可能性：

所以我尝试了一种非常天真的方法：

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。我真的很喜欢并行运行测试，但是在文档中我找不到任何相关内容。也许我不知道我应该找什么？

Answer 1

这项工作对您有用吗？

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);
        });

您可能想拥有一个AfterAll挂钩来清理数据库

如何在beforeAll / beforeEach和Jest中的测试之间共享数据？

1 个答案: