After:
  unlet! g:error_lines

Execute (stylelint errors should be handled correctly):
  " Stylelint includes trailing spaces for output. This needs to be taken into
  " account for parsing errors.
  AssertEqual
  \ [
  \   {
  \     'lnum': 108,
  \     'col': 10,
  \     'type': 'E',
  \     'text': 'Unexpected leading zero',
  \     'code': 'number-leading-zero',
  \   },
  \   {
  \     'lnum': 116,
  \     'col': 20,
  \     'type': 'E',
  \     'text': 'Expected a trailing semicolon',
  \     'code': 'declaration-block-trailing-semicolon',
  \   },
  \ ],
  \ ale#handlers#css#HandleStyleLintFormat(42, [
  \   'src/main.css',
  \   ' 108:10  ✖  Unexpected leading zero         number-leading-zero                 ',
  \   ' 116:20  ✖  Expected a trailing semicolon   declaration-block-trailing-semicolon',
  \ ])

Execute (stylelint should complain when no configuration file is used):
  let g:error_lines = [
  \ 'Error: No configuration provided for /home/w0rp/.vim/bundle/ale/test.stylus',
  \ '    at module.exports (/home/w0rp/.vim/bundle/ale/node_modules/stylelint/lib/utils/configurationError.js:8:27)',
  \ '    at stylelint._fullExplorer.load.then.then.config (/home/w0rp/.vim/bundle/ale/node_modules/stylelint/lib/getConfigForFile.js:39:13)',
  \]

  AssertEqual
  \ [{
  \   'lnum': 1,
  \   'text': 'stylelint exception thrown (type :ALEDetail for more information)',
  \   'detail': join(g:error_lines, "\n"),
  \ }],
  \ ale#handlers#css#HandleStyleLintFormat(347, g:error_lines[:])