@fakes/media-devices/src/MediaStreamFake.test.ts

A interactive fake implementation of MediaDevices interface in the browser for testing

import { defaultContext } from './context'
import { MediaStreamFake, mediaStreamId } from './MediaStreamFake'
import { anyMediaStreamTrack } from './MediaStreamTrackMother'

describe('MediaStreamFake', () => {
  test('create a new one', () => {
    expect(new MediaStreamFake(defaultContext(), mediaStreamId(), [])).toBeDefined()
  })

  test('do not leak internal state ', () => {
    const fake = new MediaStreamFake(defaultContext(), mediaStreamId(), [])
    fake.getTracks().push(anyMediaStreamTrack())
    expect(fake.getTracks()).toHaveLength(0)
  })

  test('derive active state from contained tracks', () => {
    const liveTrack = anyMediaStreamTrack({ readyState: 'live' })
    const fake = new MediaStreamFake(defaultContext(), mediaStreamId(), [liveTrack])
    expect(fake.active).toBe(true)
    liveTrack.stop()
    expect(fake.active).toBe(false)
  })

  test('filtered tracks', () => {
    const audioTrack = anyMediaStreamTrack({ kind: 'audio' })
    const videoTrack = anyMediaStreamTrack({ kind: 'video' })
    const fake = new MediaStreamFake(defaultContext(), mediaStreamId(), [audioTrack, videoTrack])
    expect(fake.getAudioTracks()).toEqual([audioTrack])
    expect(fake.getVideoTracks()).toEqual([videoTrack])
  })

  test('return track by id', () => {
    const wantedTrack = anyMediaStreamTrack({ id: 'wanted' })
    const fake = new MediaStreamFake(defaultContext(), mediaStreamId(), [wantedTrack])
    expect(fake.getTrackById('bogus')).toBe(null)
    expect(fake.getTrackById('wanted')).toBe(wantedTrack)
  })

  test('remove track', () => {
    const one = anyMediaStreamTrack()
    const two = anyMediaStreamTrack()
    const three = anyMediaStreamTrack()
    const fake = new MediaStreamFake(defaultContext(), mediaStreamId(), [one, two, three])
    const notIncluded = anyMediaStreamTrack()
    fake.removeTrack(notIncluded)
    expect(fake.getTracks()).toIncludeSameMembers([one, two, three])
    fake.removeTrack(two)
    expect(fake.getTracks()).toIncludeSameMembers([one, three])
  })
})

describe('mediaStreamId', () => {
  test('length of 36 characters', () => {
    expect(mediaStreamId()).toHaveLength(36)
  })
})