Persist require.cache after globalSetup

[faustbrian]

What is the current behaviour?

When requiring and bootstrapping a node module (singleton in my case) during the globalSetup like require('some-node-module') it will be gone if I try to get the same instance in a test via require('some-node-module').

Outside of jest this behaviour works perfectly fine since node.js caches any require call which makes it easy to provide the same instance of a module between multiple modules.

What is the expected behaviour?

After calling require('some-node-module') in the globalSetup all tests should have access to instance of require('some-node-module').

Please provide your exact Jest configuration

module.exports = {
  testEnvironment: 'node',
  moduleFileExtensions: ['js', 'json'],
  globalSetup: './__tests__/setup.js',
  setupTestFrameworkScriptFile: 'jest-extended'
}

Run npx envinfo --preset jest in your project directory and paste the
results here

  System:
    OS: macOS High Sierra 10.13.4
    CPU: x64 Intel(R) Core(TM) i5-7360U CPU @ 2.30GHz
  Binaries:
    Node: 9.11.1
    Yarn: 1.6.0
    npm: 5.8.0
  npmPackages:
    jest:
      wanted: ^22.4.3
      installed: 22.4.3

Notes

I found that jest ignores the node.js require.cache but is there some way to enable the require.cache for tests?

[SimenB]

Jest implements its own require, node's require is not run within the sandbox. Sorta related to #6058

[faustbrian]

So there is absolutely no way to achieve this with jest, not even any workarounds?

[SimenB]

Correct. It's meant to be used to e.g. setup a database (not a database connection) or start a browser (but not connect to it). Those things should be done per test (e.g. setupFiles)

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