stack traces report incorrect line numbers using coffee-script test files with mocha, chai

Not sure if this is due to an issue with Mocha or Chai, but I believe it isn’t, since running Mocha alone on the test file reports the line number correctly.

package.json

{
  "dependencies": {
    "chai": "^1.9.1",
    "coffee-script": "^1.7",
    "mocha": "1.21.3",
    "protractor": "^1.0.0"
  }
}

source-maps-test.coffee

exports.config =
  baseUrl: 'http://localhost'
  framework: 'mocha'
  rootElement: 'html'
  allScriptsTimeout: 15000
  specs: [
    'source-maps-test.coffee'
  ]
  seleniumServerJar: null
  seleniumPort: null
  seleniumAddress: null
  mochaOpts:
    compilers: 'coffee:coffee-script/register'

source-maps-test.coffee

chai = require 'chai'
expect = chai.expect

describe 'when using coffee-script files', ->
  it 'reports the correct line number of the error', ->
    expect("the line number of this error").to.equal 6 # but it reports 10

output from ‘protractor source-maps-test-config.coffee’

Starting selenium standalone server...
Selenium standalone server started at http://192.168.1.11:57696/wd/hub

  1) when using coffee-script files reports the correct line number of the error

  0 passing (19ms)
  1 failing

  1) when using coffee-script files reports the correct line number of the error:
     AssertionError: expected 'the line number of this error' to equal 6
      at Context.<anonymous> (/Users/grockit/workspace/source-maps-test/source-maps-test.coffee:10:57)
      at /Users/grockit/workspace/source-maps-test/node_modules/protractor/node_modules/selenium-webdriver/testing/index.js:131:24
      at webdriver.promise.ControlFlow.runInNewFrame_ (/Users/grockit/workspace/source-maps-test/node_modules/protractor/node_modules/selenium-webdriver/lib/webdriver/promise.js:1539:20)
      at webdriver.promise.ControlFlow.runEventLoop_ (/Users/grockit/workspace/source-maps-test/node_modules/protractor/node_modules/selenium-webdriver/lib/webdriver/promise.js:1404:8)
      at wrapper [as _onTimeout] (timers.js:252:14)
      at Timer.listOnTimeout [as ontimeout] (timers.js:110:15)
  ==== async task ====
      at Context.ret (/Users/grockit/workspace/source-maps-test/node_modules/protractor/node_modules/selenium-webdriver/testing/index.js:129:14)
      at Test.Runnable.run (/Users/grockit/workspace/source-maps-test/node_modules/mocha/lib/runnable.js:214:15)
      at Runner.runTest (/Users/grockit/workspace/source-maps-test/node_modules/mocha/lib/runner.js:373:10)
      at /Users/grockit/workspace/source-maps-test/node_modules/mocha/lib/runner.js:451:12
      at next (/Users/grockit/workspace/source-maps-test/node_modules/mocha/lib/runner.js:298:14)
      at /Users/grockit/workspace/source-maps-test/node_modules/mocha/lib/runner.js:308:7
      at next (/Users/grockit/workspace/source-maps-test/node_modules/mocha/lib/runner.js:246:23)
      at Object._onImmediate (/Users/grockit/workspace/source-maps-test/node_modules/mocha/lib/runner.js:275:5)
      at processImmediate [as _immediateCallback] (timers.js:330:15)

output from ‘mocha --compilers coffee:coffee-script/register source-maps-test.coffee’:

  when using coffee-script files
    1) reports the correct line number of the error


  0 passing (5ms)
  1 failing

  1) when using coffee-script files reports the correct line number of the error:
     AssertionError: expected 'the line number of this error' to equal 6
    at Context.<anonymous> (/Users/grockit/workspace/source-maps-test/source-maps-test.coffee:6:48)
    at callFn (/Users/grockit/workspace/source-maps-test/node_modules/mocha/lib/runnable.js:247:21)
    at Test.Runnable.run (/Users/grockit/workspace/source-maps-test/node_modules/mocha/lib/runnable.js:240:7)
    at Runner.runTest (/Users/grockit/workspace/source-maps-test/node_modules/mocha/lib/runner.js:373:10)
    at /Users/grockit/workspace/source-maps-test/node_modules/mocha/lib/runner.js:451:12
    at next (/Users/grockit/workspace/source-maps-test/node_modules/mocha/lib/runner.js:298:14)
    at /Users/grockit/workspace/source-maps-test/node_modules/mocha/lib/runner.js:308:7
    at next (/Users/grockit/workspace/source-maps-test/node_modules/mocha/lib/runner.js:246:23)
    at Object._onImmediate (/Users/grockit/workspace/source-maps-test/node_modules/mocha/lib/runner.js:275:5)
    at processImmediate [as _immediateCallback] (timers.js:330:15)

[rbrcurtis]

That’s it really. npm install coffee-errors --save, then in our protractor-conf file, we have

  onPrepare: ->
    require 'coffee-errors'

That’s enough to fix line numbers in all test exceptions.

[juliemr]

I’m going to close this as infeasible - we don’t want Protractor to duplicate build pipelines, so we won’t be including custom configurations for different compilers. Solutions like coffee-errors are the right way to go.