Before:
  runtime! ale_linters/scala/scalastyle.vim

After:
  call ale#linter#Reset()

Execute(The scalastyle handler should parse lines correctly):
  AssertEqual
  \ [
  \   {
  \     'lnum': 190,
  \     'text': 'Missing or badly formed ScalaDoc: Missing @param str',
  \     'type': 'W',
  \   },
  \   {
  \     'lnum': 200,
  \     'col': 34,
  \     'text': 'There should be a space before the plus (+) sign',
  \     'type': 'E',
  \   },
  \   {
  \     'lnum': 200,
  \     'col': 1,
  \     'text': 'There should be a space before the plus (+) sign',
  \     'type': 'E',
  \   },
  \ ],
  \ ale_linters#scala#scalastyle#Handle(347, [
  \    'Starting scalastyle',
  \    'start file /home/test/Doop.scala',
  \    'warning file=/home/test/Doop.scala message=Missing or badly formed ScalaDoc: Missing @param str line=190',
  \    'error file=/home/test/Doop.scala message=There should be a space before the plus (+) sign line=200 column=33',
  \    'error file=/home/test/Doop.scala message=There should be a space before the plus (+) sign line=200 column=0',
  \    'end file /home/test/Doop.scala',
  \    'Processed 1 file(s)',
  \    'Found 0 errors',
  \    'Found 3 warnings',
  \    'Finished in 934 ms',
  \ ])

Execute(The scalastyle linter should complain when there is no configuration file):
  AssertEqual
  \ [
  \   {
  \     'lnum': 1,
  \     'text': '(See :help ale-scala-scalastyle) No scalastyle configuration file was found.',
  \   },
  \ ],
  \ ale_linters#scala#scalastyle#Handle(347, [
  \   'scalastyle 1.0.0',
  \   'Usage: scalastyle [options] <source directory>',
  \   ' -c, --config FILE               configuration file (required)',
  \ ])