detect jest and use http adapter instead of XMLhttpRequest

So I had a peculiar evening. We have an unconventional test suite in Jest. We run it in the regular mode, not with "testEnvironment": "node" so it has window. In one test I was trying to fetch something with axios, but it always broke down and showed me a Network error. I was banging my head against the table and had a nice debug session and eventually found out this thread: https://stackoverflow.com/questions/42677387/jest-returns-network-error-when-doing-an-authenticated-request-with-axios Which was awesome. Using this spectacular hack:

if (process.env.LOOOP_ENVIRONMENT === 'test') {
    const path = require('path') 
    const lib = path.join(
      path.dirname(require.resolve('axios')),
      'lib/adapters/http'
    )
    const http = require(lib)
    config.adapter = http
  }

I was able resolve the problem. What I want to suggest is-since jest is very popular test runner and a lot of people are running jest in regular mode, not in node they will often bang their heads.

Maybe it would be good to detect when we’re running in jest and refrain from using XMLHttpRequest? Is that too much to ask?

[kmarkow]

I’ve had a fun afternoon too. I solved it by adding testEnvironment: 'node', to jest.config.js file.

By default jest runs tests in jsdom mode which adds XmlHttpRequest to global scope which in turns causes axios to think it’s running in a browser and making requests via XmlHttpRequest instead of node’s native library.

[mpacary]

If you need to keep jsdom as testEnvironment (Vue components testing…), here is another nice workaround:

Add global.XMLHttpRequest = undefined in your Jest setup file.