Libraries that use Symbol properties on builtin prototypes break in Jest

[cowboyd]

Do you want to request a feature or report a bug?
bug

What is the current behavior?

Libraries that add Symbols to builtins like Object.prototype and Array.prototype for unique, anonymous properties break using Jest.

If the current behavior is a bug, please provide the steps to reproduce and either a repl.it demo through https://repl.it/languages/jest or a minimal repository on GitHub that we can yarn install and yarn test.

demonstration of the problem

What is the expected behavior?

Symbol properties can be added to builtin prototypes. This works IRL in node, browser, and other testing frameworks.

Please provide your exact Jest configuration and mention your Jest, node, yarn/npm version and operating system.

$ node --version
v8.5.0
$ yarn test --version                                                                   ⏎
yarn test v1.0.2
$ jest "--version"
v21.2.1
✨  Done in 0.26s.
$ uname -a
Darwin 16.7.0 Darwin Kernel Version 16.7.0: Thu Jun 15 17:36:27 PDT 2017; root:xnu-3789.70.16~2/RELEASE_X86_64 x86_64

[ladyleet]

Wish it would jest work! 👯👏😂👍

[taras]

Jest tests run in JSDOM. JSDOM uses Node.js VM to run tests in isolation with window object. Unfortunately, modules imported by require run in original node context. So, funcadelic works as expected by the typeclass implementations are added to Node context rather than VM context.

I created a test-setup.js file and added it to jest with

  "jest": {
    "testRegex": "(/tests/.*|\\.(test|spec))\\.(js)$",
    "setupTestFrameworkScriptFile": "<rootDir>/test-setup.js"
  }

Inside of test-setup.js, I'm calling require but it's still running in original node's context not VM's context. The require inside of VM is a wrapper provided by jest-mock library. It seems that this library might be bound incorrectly to node instance rather than the VM instance.

There are several related issues in Node & Jest repoes

• node_contextify tracking issue
• vm: references to context inside objects are not === the original context
• Jest globals differ from Node globals

[cowboyd]

Is there a workaround for this? I.e. to direct jest to say which modules should be run in the VM context?

[github-actions]

This issue is stale because it has been open for 1 year with no activity. Remove stale label or comment or this will be closed in 30 days.

[cowboyd]

good times!

[github-actions]

This issue is stale because it has been open for 1 year with no activity. Remove stale label or comment or this will be closed in 30 days.

[github-actions]

This issue was closed because it has been stalled for 30 days with no activity. Please open a new issue if the issue is still relevant, linking to this one.

[github-actions]

This issue has been automatically locked since there has not been any recent activity after it was closed. Please open a new issue for related bugs.
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