nflow/test/spec/cancellation.js

event/data/control flow

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

var sut

describe('Cancellation', function () {
  beforeEach(function () {
    sut = flow
      .create('sut')
      .parent(null)
  })
  describe('Flow Cancellation', function () {
    it('parent node should cancel all child nodes', function () {
      var a = sut.create('a') // parent
      var a1 = a.create('a1') // parent's sibling
      var b = a.create('b')   // SUT
      var b1 = a.create('b1') // sibling
      var c = b.create('c')   // child
      var c1 = b.create('c1') // child
      var d = c.create('d')   // grandchild

      b.cancel()

      // falsy
      expect(a.isCancelled()).to.be.false
      expect(a1.isCancelled()).to.be.false
      expect(sut.isCancelled()).to.be.false
      expect(b1.isCancelled()).to.be.false

      // truthy
      expect(b.isCancelled()).to.be.true
      expect(c.isCancelled()).to.be.true
      expect(c1.isCancelled()).to.be.true
      expect(d.isCancelled()).to.be.true
    })

    it('should cancel event delegation.', function (done) {
      function shouldCall () {
        this.cancel()
      }
      function shouldNotCall () {
        done('cancelled event should not call subsequent listeners')
      }

      sut
        .create('a') // parent
        .on('test', shouldNotCall)
        .create('b')
        .on('test', shouldCall)
        .create('c')
        .emit('test')

      setTimeout(done, 10)
    })

    it('should cancel event delivery on same listener', function (done) {
      function shouldCall () {
        this.cancel()
      }
      function shouldNotCall () {
        done('cancelled event should not call subsequent listeners')
      }

      sut
        .create('b')
        .on('test', shouldCall, shouldNotCall)
        .create('c')
        .emit('test')

      setTimeout(done, 10)
    })

    it('should not emit events on cancelled nodes', function (done) {
      function shouldNotCall () {
        done('cancelled event should not call subsequent listeners')
      }

      sut
        .create('b')
        .cancel()
        .create('c')
        .on('test', shouldNotCall)
        .create('d')
        .emit('test')

      setTimeout(done, 10)
    })
    it('should not deliver events into a cancelled subtree', function (done) {
      function shouldCall () {
        done()
      }
      function shouldNotCall () {
        done('stopped event should not call listener')
      }
      var a = sut.create('a')
        .on('test', shouldNotCall)
      a.create('b')
        .on('test', shouldNotCall)

      var c = sut.create('c')
      c.create('d')
        .on('test', shouldCall)

      a.cancel()
      c.emit('test')
    })
  })
})