Jest Warnings: You are trying to import a file after the Jest environment has been torn down.

[IPWright83]

Describe the bug

Getting lots of warnings when running tests with Jest:

ReferenceError: You are trying to import a file after the Jest environment has been torn down.

 at reportLogBoxError (node_modules/react-native/Libraries/LogBox/Data/LogBoxData.js:95:27)
 at Immediate._onImmediate (node_modules/react-native/Libraries/LogBox/Data/LogBoxData.js:201:7)

/home/iw***/src/mobileApp/myuoy/node_modules/react-native/Libraries/LogBox/Data/LogBoxData.js:104
ExceptionsManager.handleException(error, true);

I believe that this is likely this library due to testing-library/native-testing-library#132 but I may be wrong

Expected behavior

No warnings

Steps to Reproduce

I'm not exactly sure, as I don't know where this is being triggered from. The stack trace is originating within LogBoxData.

Versions

npmPackages:
    @testing-library/react-native: ^7.1.0 => 7.1.0 
    react: 16.13.1 => 16.13.1 
    react-native: 0.63.2 => 0.63.2 
    react-test-renderer: 16.13.1 => 16.13.1 

[thymikee]

This is not related to this library. It's something that likely should be mocked in the official react-native jest preset. Feel free to propose such change. Meanwhile you should be good with e.g. this:

jest.mock('react-native/Libraries/LogBox/LogBox');

[IPWright83]

Thanks @thymikee - especially for the suggestion rather than just a close.

[thymikee]

Yea, it's a bummer it's not properly mocked in the source, but I believe it should be done there, instead of just patching it in this library. That's why I encourage folks to target their efforts to the right place.

[sabun123]

@thymikee, I just wanted to thank you for the mock you suggested. It solved my issue.

I was previously on React Native 0.63.3 with @testing-library/react-native version 7.1.0 and my jest unit tests worked fine. After upgrading to React Native 0.64 and React 17.0.1 I started experiencing Jest failing the entire suite with :

/Users/USER/Documents/code/project-name/node_modules/react-native/Libraries/LogBox/Data/LogBoxData.js:104
  ExceptionsManager.handleException(error, true);
  
  TypeError: ExceptionsManager.handleException is not a function
    at reportLogBoxError (/Users/USER/Documents/code/project-name/node_modules/react-native/Libraries/LogBox/Data/LogBoxData.js:108:21)
    at Immediate.<anonymous> (/Users/USER/Documents/code/project-name/node_modules/react-native/Libraries/LogBox/Data/LogBoxData.js:214:7)

After adding the following lines to my jest/setup.js file, everything works again!

jest.mock('react-native/Libraries/LogBox/LogBox');

It's unfortunate that an upgrade to React Native can still break unit tests at a fundamental level like this, but your answer is a lifesaver for those of us in production work.