当我尝试在异步函数上使用toThrow（）时，Jest Test记录了一个错误（但仍通过测试）

debugcn 发表于 Dev

10110

我正在尝试使用Jest测试异步功能。到目前为止，我似乎通过了三个测试。

但是，测试完成运行后，我得到一个错误UnhandledPromiseRejectionWarning: Error: expect(received).toThrow(expected)...（请参阅下面的完整日志）。我已经尝试过在此处以及在GitHub上这样的其他地方发布的多种解决方案，但是我无法摆脱错误。

我有以下异步功能：

async function aliasIsAdmin(alias, roles = DEFAULT_ROLES) {
  try {
    const url = "https://xxxxxx.execute-api.us-west-2.amazonaws.com/local/xxxxx/";
    if (typeof alias !== "string") {
      throw new Error('Entity "alias" must be a string.');
    }

    if(!Array.isArray(roles)){
      throw new Error('Entity "roles" must be an array but got "' + typeof roles + '". Permission Denied.');
    } 
    else if(roles.some((role) => typeof role !== "string")){
      throw 'Entity "roles" must be an array of strings but got at least one element of type: "' + typeof alias + '". Permission Denied.';
    }

    let { data } = (await axios.get(url + alias)); //Fetch roles that the alias holds.
    return data.some((role) => roles.includes(role)); //If alias has any of the roles in the policy, grant access.

  } catch (error) {
    console.error("Error when attempting to authorize user @" + alias
      + ". Access for this user has been denied, please try again.\nError:\n" + error);
    return false;
  }
}

我编写了以下测试：

const { aliasIsAdmin, getRolesByAlias } = require("../authorization");

describe('aliasIsAdmin', () => {
    it('should return true', () => {
        expect.assertions(1);
        return aliasIsAdmin("anAdmin")
        .then((r => {expect(r).toBe(true)}));
      });
    
    it('should return false', () => {
    expect.assertions(1);
    return aliasIsAdmin("notAnAdmin")
    .then((r => {expect(r).toBe(false)}));
    });

    it('should throw', () => {
        aliasIsAdmin(1)
        .then((r => {expect(r).toThrow('Entity "alias" must be a string.')}));
        });
});

当我运行测试时，我得到：

(node:94497) UnhandledPromiseRejectionWarning: Error: expect(received).toThrow(expected)

Matcher error: received value must be a function

Received has type:  boolean
Received has value: false
(node:94497) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). (rejection id: 1)
(node:94497) [DEP0018] DeprecationWarning: Unhandled promise rejections are deprecated. In the future, promise rejections that are not handled will terminate the Node.js process with a non-zero exit code.
PASS  public/utils/test/authorization.test.js
  aliasIsAdmin
    ✓ should return true (895 ms)
    ✓ should return false (238 ms)
    ✓ should throw (37 ms)

  console.error
    Error when attempting to authorize user @1. Access for this user has been denied, please try again.
    Error:
    Error: Entity "alias" must be a string.

      41 | 
      42 |   } catch (error) {
    > 43 |     console.error("Error when attempting to authorize user @" + alias
         |             ^
      44 |       + ". Access for this user has been denied, please try again.\nError:\n" + error);
      45 |     return false;
      46 |   }

      at aliasIsAdmin (public/utils/authorization.js:43:13)
      at Object.<anonymous> (public/utils/test/authorization.test.js:17:9)
Test Suites: 1 passed, 1 total
Tests:       3 passed, 3 total
Snapshots:   0 total

我的测试命令是： jest --coverage public/utils/test

EOL

如错误消息所述，toThrow期望函数作为其接收值，在您的情况下，这是一个Promise解析的布尔值，因为您在aliasIsAdmincatch块中捕获了所有错误并返回false。

如果更改catch块中的逻辑并重新引发错误，则可以在单元测试中使用以下内容：

it('should throw', async () => {
      await expect(aliasIsAdmin(1)).rejects.toThrow('Entity "alias" must be a string.');
});

如果当前逻辑是正确的，并且您实际上并不希望引发错误，则需要更改单元测试以检查已解析的false布尔值：

it('should return false if non-string parameter is passed', async () => {
      const result = await aliasIsAdmin(1);
      expect(result).toBe(false);
});

本文收集自互联网，转载请注明来源。

如有侵权，请联系[email protected] 删除。