JavaScript Testing Best Practices: Part 2

backbone_render.coffee

view = Backbone.View.extend
  initialize:
    @render()

  render:
    $el.html('<div class="content">fun times</div>')

jasmine.yml

src_files:
  # your normal script files

helpers:
  - helpers/suiteHealthHelper.js

spec_files:
  - "**/*[sS]pec.js"
  - spec/javascripts/support/suite_health.js

section_comment.coffee

# calculate total
subtotal = getSubTotal()
state = getState()
tax = getTax(subtotal, state)
discounts = getDiscounts()
total = subtotal + tax - discounts

section_comment_fixed.coffee

calculateTotal = ->
  subtotal = getSubTotal()
  state = getState()
  tax = getTax(subtotal, state)
  discounts = getDiscounts()
  return subtotal + tax - discounts

suite_health.coffee

describe 'Jasmine Suite', ->
  it 'has no errors from window.onerror', ->
    expect(JSON.stringify(window.__errors)).toBe('[]')

  describe 'does not pollute global state', ->
    it 'by setting cookies', ->
      expect(document.cookie).toBe('')

    it 'by setting local storage values', ->
      actual = ''
      for key in localStorage
        value = localStorage.getItem(key)
        actual += "#{key}:#{value};"

      expect(actual).toBe('')

    it 'by setting session storage values', ->
      actual = ''
      for key in sessionStorage
        value = sessionStorage.getItem(key)
        actual += "#{key}:#{value};"

      expect(actual).toBe('')

    it 'by leaving DOM elements in the document', ->
      $pollution = $('body>*:not(#jasmine_content, .jasmine_reporter)')
      expected = "Pollution Elements Count: #{$pollution.length}"
      expect(expected).toBe("Pollution Elements Count: 0")

  describe 'does not log to the console', ->
    it 'with console.log', ->
      expect(JSON.stringify(window.consoleLogs)).toBe('[]')

    it 'with console.dir', ->
      expect(JSON.stringify(window.consoleDirs)).toBe('[]')

    it 'with console.warn', ->
      expect(JSON.stringify(window.consoleWarns)).toBe('[]')

    it 'with console.error', ->
      expect(JSON.stringify(window.consoleErrors)).toBe('[]')

suite_health_helper.coffee

window.__errors = []
window.onerror = (message, file, line) ->
  window.__errors.push
    message: message
    file: file
    line: line
  return false

if (window.addEventListener)
  window.addEventListener 'onerror', (message, file, line) ->
    window.__errors.push
      message: message
      file: file
      line: line
    return false

window.consoleLogs = []
window.consoleDirs = []
window.consoleWarns = []
window.consoleErrors = []

if (window['console'])
  _consoleLog = console.log
  window.console.log = (message) ->
    _consoleLog(message)
    window.consoleLogs.push(message)

  _consoleDir = console.dir
  window.console.dir = (message) ->
    _consoleDir(message)
    window.consoleDirs.push(message)

  _consoleWarn = console.warn
  window.console.warn = (message) ->
    _consoleWarn(message)
    window.consoleWarns.push(message)

  _consoleError = console.error
  window.console.error = (message) ->
    _consoleError(message)
    window.consoleErrors.push(message)

window.alert = (message) ->
  errorMessage = 'Cannot call alert in specs. Called with: ' + message
  throw new Error(errorMessage)

window.confirm = (message) ->
  errorMessage = 'Cannot call confirm in specs. Called with: ' + message
  throw new Error(errorMessage)

todo_comment.coffee

#TODO: Move this to another file
processOrders = ->