无法使用"fetch mock jest 1.5.1"lib模拟fetch调用

Question

我试图使用thisfetch-mock-jest模拟一个fetch调用，但代码仍然试图转到远程地址，最终失败，并返回错误消息FetchError: request to https://some.domain.io/app-config.yaml failed, reason: getaddrinfo ENOTFOUND some.domain.io]。

这里是测试代码

import { AppConfig } from '@backstage/config';
import { loadConfig } from './loader';
import mockFs from 'mock-fs';
import fetchMock from 'fetch-mock-jest';
describe('loadConfig', () => {
beforeEach(() => {
fetchMock.mock({
matcher: '*',
response: `app:
title: Example App
sessionKey: 'abc123'
`
});
});
afterEach(() => {
fetchMock.mockReset();
});
it('load config from remote path', async () => {
const configUrl = 'https://some.domain.io/app-config.yaml';
await expect(
loadConfig({
configRoot: '/root',
configTargets: [{ url: configUrl }],
env: 'production',
remote: {
reloadIntervalSeconds: 30,
},
})
).resolves.toEqual([
{
context: configUrl,
data: {
app: {
title: 'Example App',
sessionKey: 'abc123',
},
},
},
]);
expect(fetchMock).toHaveBeenCalledTimes(1);
});
function defer<T>() {
let resolve: (value: T) => void;
const promise = new Promise<T>(_resolve => {
resolve = _resolve;
});
return { promise, resolve: resolve! };
}
});

loadConfig有我试图模拟的获取代码。

export async function loadConfig(
options: LoadConfigOptions,
): Promise<AppConfig[]> {
const loadRemoteConfigFiles = async () => {
const configs: AppConfig[] = [];
const readConfigFromUrl = async (remoteConfigProp: RemoteConfigProp) => {
const response = await fetch(remoteConfigProp.url);
if (!response.ok) {
throw new Error(
`Could not read config file at ${remoteConfigProp.url}`,
);
}
remoteConfigProp.oldETag = remoteConfigProp.newETag ?? undefined;
remoteConfigProp.newETag =
response.headers.get(HTTP_RESPONSE_HEADER_ETAG) ?? undefined;
remoteConfigProp.content = await response.text();
return remoteConfigProp;
};
.......
return configs;
}
let remoteConfigs: AppConfig[] = [];
if (remote) {
try {
remoteConfigs = await loadRemoteConfigFiles();
} catch (error) {
throw new Error(`Failed to read remote configuration file, ${error}`);
}
}
........ do some stuff with config then return
return remoteConfigs;
}

config是一个yaml文件，它最终被解析并转换为config对象。

知道为什么它没能模拟fetch调用吗？

Answer 1

取代

import fetchMock from 'fetch-mock-jest';

带有

const fetchMock = require('fetch-mock').sandbox();
const nodeFetch = require('node-fetch');
nodeFetch.default = fetchMock;

CCD_ 3与CCD_ 4