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 [number-leading-zero]',
  \   },
  \   {
  \     'lnum': 116,
  \     'col': 20,
  \     'type': 'E',
  \     'text': 'Expected a trailing semicolon [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',
  \ ])