koel/resources/assets/js/utils/eventBus.spec.ts

import UnitTestCase from '@/__tests__/UnitTestCase'
import { expect, it, vi } from 'vitest'
import { eventBus } from './eventBus'

new class extends UnitTestCase {
  protected beforeEach () {
    super.beforeEach(() => (eventBus.all = new Map()))
  }

  protected test () {
    it('listens on a single event', () => {
      const mock = vi.fn()
      eventBus.on('SHOW_OVERLAY', mock)

      eventBus.emit('SHOW_OVERLAY')

      expect(mock).toHaveBeenCalledOnce()
    })

    it('listens with parameters', () => {
      const mock = vi.fn()
      eventBus.on('SHOW_OVERLAY', mock)

      eventBus.emit('SHOW_OVERLAY', 'foo', 'bar')

      expect(mock).toHaveBeenNthCalledWith(1, 'foo', 'bar')
    })

    it('registers multiple listeners at once', () => {
      const mock1 = vi.fn()
      const mock2 = vi.fn()

      eventBus.on({
        SHOW_OVERLAY: mock1,
        MODAL_SHOW_ABOUT_KOEL: mock2
      })

      eventBus.emit('SHOW_OVERLAY')
      expect(mock1).toHaveBeenCalledOnce()

      eventBus.emit('MODAL_SHOW_ABOUT_KOEL')
      expect(mock2).toHaveBeenCalledOnce()
    })

    it('queue up listeners on same event', () => {
      const mock1 = vi.fn()
      const mock2 = vi.fn()
      eventBus.on('SHOW_OVERLAY', mock1)
      eventBus.on('SHOW_OVERLAY', mock2)

      eventBus.emit('SHOW_OVERLAY')

      expect(mock1).toHaveBeenCalledOnce()
      expect(mock2).toHaveBeenCalledOnce()
    })
  }
}