React-native: Jest - testMatch and testRegex cannot be used together with RN 0.59.1

[NemanjaManot]

🐛 Bug Report

I had project on 0.58.0 and upgraded to 0.59.1 and jest tests stopped working with an error

● Validation Error:

Configuration options testMatch and testRegex cannot be used together.

Configuration Documentation:
https://jestjs.io/docs/configuration.html

This is my jest configuration in package.json:

  "jest": {
    "preset": "react-native",
    "transform": {
      "^.+\\.js$": "<rootDir>/node_modules/react-native/jest/preprocessor.js"
    },
    "transformIgnorePatterns": [
      "node_modules/(?!react-native|react-navigation)"
    ],
    "setupFiles": [
      "<rootDir>/__mocks__/mocks.js"
    ],
    "globals": {
      "window": {}
    },
    "testRegex": "(/__tests__/.*|\\.(test))\\.jsx?$"
  }

Nowhere do I have testMatch.

To Reproduce

Have 0.58 project and upgrade to 0.59.1

Expected Behavior

Tests to start running

Code Example

Environment

  React Native Environment Info:
    System:
      OS: Ubuntu 18.04.2 LTS
      CPU: Intel® Core™ i5-4440 CPU @ 3.10GHz × 4 
      Memory: 15,6 GiB
    Binaries:
      Node: 10.10.0
      npm: 6.4.1 
      Watchman: 4.9.0 - /usr/local/bin/watchman
    IDEs:
      Android Studio: 3.4.1
    npmPackages:
      react: 16.8.4 
      react-native: 0.59.1

[thymikee]

You're using react-native Jest preset, which includes testMatch, that's why you get the error. Please consider changing testRegex to testMatch (or just remove it) for now.

Btw, it seems like the testMatch config in RN preset
https://github.com/facebook/react-native/blob/02e8e531ddfd86e9abf7ef47fbf30445afeb37cf/jest-preset.js#L33-L36

pretty much aligns with the default from Jest 24:
https://github.com/facebook/jest/blob/c5fd7aae93764c13c259ae9a73846c10e84ae2a3/packages/jest-config/src/Defaults.ts#L70

So soon enough we should be able to get rid of this from the config.

To satisfy "working with TypeScript by default" constraint though, RN would need to require Jest 24+. @cpojer are we good to change it in 0.60 (I believe we are)?

[cpojer]

@thymikee yeah, the latest Jest 24 should be part of RN on master.