nflow/test/spec/listener.js

event/data/control flow

/* globals describe, it, beforeEach */
import flow from 'nflow'
import {expect} from 'chai'
var sut

describe('Listeners', function () {
  beforeEach(function () {
    sut = flow
      .create('sut')
      .parent(null)
  })
  describe('on() API', function () {
    it('should store single listener', function () {
      var listener = function () {}
      sut.on('foo', listener)
      expect(sut.on('foo')).to.eql([listener])
    })

    it('should store multiple listeners', function () {
      var listener1 = function () {}
      var listener2 = function () {}
      sut.on('foo', listener1, listener2)
      expect(sut.on('foo')).to.eql([listener1, listener2])
    })

    it('return undefined for non-existent listeners', function () {
      expect(sut.on('non-existent')).to.be.undefined
    })

    it('should destroy single listener', function () {
      var listener = function () {}
      sut.on('foo', listener)
      sut.on('foo', null)
      expect(sut.on('foo')).to.be.undefined
    })

    it('should destroy multiple listeners', function () {
      var listener = function () {}
      var listener1 = function () {}
      sut.on('foo', listener, listener1)
      sut.on('foo', null)
      expect(sut.on('foo')).to.be.undefined
    })

    it('should store multiple listeners', function () {
      var listener1 = function () {}
      var listener2 = function () {}
      sut.on('foo', listener1, listener2)
      expect(sut.on('foo')).to.eql([listener1, listener2])
    })

    it('should ignore invalid listeners', function () {
      var listener1 = function () {}
      var listener2 = function () {}
      try {
        sut.on('foo', listener1, 'invalid', listener2)
      } catch (e) {
        expect(e).to.be.an.error
      }
      expect(sut.on('foo')).to.be.undefined
    })
  })
})