Testing with Jest: Tip #9

package.json

{
  "jest": {
    "setupFiles": [
      "<rootDir>/test-setup.js"
    ]
  }
}

test-setup.js

// In Node v7 unhandled promise rejections will terminate the process
if (!process.env.LISTENING_TO_UNHANDLED_REJECTION) {
  process.on('unhandledRejection', reason => {
    throw reason
  })
  // Avoid memory leak by adding too many listeners
  process.env.LISTENING_TO_UNHANDLED_REJECTION = true
}