when testing an application which loads separate modules globals are not propagated and the modules run in a separate context

🐛 Bug Report

I have an application that loads extra code as Module to override the “require” mechanic and isolate the code. This works well when running in directly in node and globals are propagated to the modules (they share the same virtual context).

However, when running the code in Jest it starts to fail with “document is not defined” and also with issues when using instanceof since objects have been created in different contexts.

To Reproduce

• setup a global
• load another file as a new Module
• try to access the global in the module
• ->You will get an error MY_GLOBAL is not defined

Expected behavior

• The global exists and can be accessed

Link to repl or repo (highly encouraged)

https://github.com/technicallyfeasible/jest-module

Run npx envinfo --preset jest

Paste the results here:

  System:
    OS: Windows 10
    CPU: x64 Intel(R) Core(TM) i7-5600U CPU @ 2.60GHz
  Binaries:
    Yarn: 1.6.0 - ~AppData\Roaming\npm\yarn.CMD
    npm: 6.0.0 - ~AppData\Roaming\npm\npm.CMD

[technicallyfeasible]

I was actually able to fix my particular problem by using a custom environment and passing the globals that I need through manually:

const JsDomEnvironment = require('jest-environment-jsdom');


class JestCustomEnvironment extends JsDomEnvironment {
  async setup() {
    await super.setup();
    global.document = this.global.document;
    global.window = this.global.window;
    global.jsdom = this.global.jsdom;
  }
}

module.exports = JestCustomEnvironment;

And pass it in the config:

“testEnvironment”: “./JestCustomEnvironment.js”,

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