jest-launchdarkly-mock

Caution

This package is only compatible with the Launchdarkly React SDK. There is a new major version of the React SDK in our js-core monorepo. At this time, we are NOT planning to update this package to be compatible with the new major version. Please see our docs for mock testing recommendations.

Easily unit test LaunchDarkly feature flagged components with jest 👏

Installation

yarn add -D jest-launchdarkly-mock

or

npm install jest-launchdarkly-mock --save-dev

Then in jest.config.js add jest-launchdarkly-mock to setupFiles:

// jest.config.js
module.exports = {
  setupFiles: ['jest-launchdarkly-mock'],
}

Usage

Use the only 3 apis for test cases:

• mockFlags(flags: LDFlagSet): mock flags at the start of each test case. Only mocks flags returned by the useFlags hook.

• ldClientMock: a jest mock of the ldClient. All methods of this object are jest mocks.

• resetLDMocks : resets both mockFlags and ldClientMock.

Example

import { mockFlags, ldClientMock, resetLDMocks } from 'jest-launchdarkly-mock'

describe('button', () => {
  beforeEach(() => {
    // reset before each test case
    resetLDMocks()
  })

  test('flag on', () => {
      // arrange
      // You can use the original unchanged case, kebab-case, camelCase or snake_case keys.
      mockFlags({ devTestFlag: true })
  
      // act
      const { getByTestId } = render(<Button />)

      // assert
      expect(getByTestId('test-button')).toBeTruthy()
    })

  test('identify', () => {
    // arrange
    mockFlags({ 'dev-test-flag': true })
    
    // act
    const { getByTestId } = render(<Button />)
    fireEvent.click(getByTestId('test-button'))

    // assert: identify gets called
    expect(ldClientMock.identify).toBeCalledWith({ key: 'aa0ceb' })
  })
})