How to test React PropTypes through Jest?

Question

I\'m writing Jest tests for my React code and hoping to make use of/test the PropType checks. I am quite new to the Javascript universe. I\'m using npm to install reac

Answer 1

For unit tests based on Jest, using this on your setup.js will fail any test where console.error (prop-type errors) or console.warn (React compat issues, like still using componentWillUpdate) ends up being called:

beforeEach(() => {
  jest.spyOn(console, 'error')
  jest.spyOn(console, 'warn')
})

afterEach(() => {
  /* eslint-disable no-console,jest/no-standalone-expect */
  expect(console.error).not.toBeCalled()
  expect(console.warn).not.toBeCalled()
})

This breaks when any test calls jest.restoreAllMocks() - for us, calling jest.clearAllMocks()` instead helped.

It also requires your app to not call console.error or console.warn for "error handling" (scare quotes, since that's usually not a good idea).