Before:
  runtime ale_linters/java/checkstyle.vim

After:
  call ale#linter#Reset()

Execute(The checkstyle handler should parse lines correctly):
  AssertEqual
  \ [
  \   {
  \     'lnum': 101,
  \     'col': 0,
  \     'text': '''method def rcurly'' has incorrect indentation level 4, expected level should be 2.',
  \     'code': 'Indentation',
  \     'type': 'W',
  \     'sub_type': 'style',
  \   },
  \   {
  \     'lnum': 63,
  \     'col': 3,
  \     'text': 'Missing a Javadoc comment.',
  \     'code': 'JavadocMethod',
  \     'type': 'W',
  \     'sub_type': 'style',
  \   },
  \   {
  \     'lnum': 11,
  \     'col': 7,
  \     'text': 'WhitespaceAround: ''if'' is not followed by whitespace.',
  \     'code': 'WhitespaceAround',
  \     'type': 'W',
  \     'sub_type': 'style',
  \   },
  \ ],
  \ ale_linters#java#checkstyle#Handle(666, [
  \   '[WARN] whatever:101: ''method def rcurly'' has incorrect indentation level 4, expected level should be 2. [Indentation]',
  \   '[WARN] whatever:63:3: Missing a Javadoc comment. [JavadocMethod]',
  \   '[WARN] whatever:11:7: WhitespaceAround: ''if'' is not followed by whitespace. [WhitespaceAround]',
  \ ])

Execute(The checkstyle handler should parse lines from older checkstyle versions correctly):
  AssertEqual
  \ [
  \   {
  \     'lnum': 289,
  \     'text': '''method def modifier'' have incorrect indentation level 4, expected level should be 2.',
  \     'type': 'W',
  \     'sub_type': 'style',
  \   },
  \ ],
  \ ale_linters#java#checkstyle#Handle(666, [
  \   '/home/languitar/src/rsb-java/rsb-java/src/main/java/rsb/Listener.java:289: warning: ''method def modifier'' have incorrect indentation level 4, expected level should be 2.',
  \ ])
