Before:
  runtime ale_linters/typescript/tslint.vim

  call ale#test#SetDirectory('/testplugin/test/handler')

After:
  call ale#test#RestoreDirectory()
  call ale#linter#Reset()

Execute(The tslint handler should parse lines correctly):
  call ale#test#SetFilename('app/test.ts')

  AssertEqual
  \ [
  \   {
  \     'lnum': 1,
  \     'col': 15,
  \     'end_lnum': 1,
  \     'end_col': 15,
  \     'text': 'Missing semicolon',
  \     'type': 'E',
  \   },
  \   {
  \     'lnum': 2,
  \     'col': 8,
  \     'end_lnum': 3,
  \     'end_col': 12,
  \     'text': 'Something else',
  \     'type': 'W',
  \   },
  \   {
  \     'lnum': 31,
  \     'col': 9,
  \     'end_lnum': 31,
  \     'end_col': 20,
  \     'text': 'Calls to console.log are not allowed.',
  \     'type': 'E',
  \   },
  \ ],
  \ ale_linters#typescript#tslint#Handle(bufnr(''), [json_encode([
  \   {
  \     'endPosition': {
  \       'character': 14,
  \       'line': 0,
  \       'position': 1000
  \     },
  \     'failure': 'Missing semicolon',
  \     'fix': {
  \       'innerLength': 0,
  \       'innerStart': 14,
  \       'innerText': ';'
  \     },
  \     'name': 'app/test.ts',
  \     'ruleName': 'semicolon',
  \     'ruleSeverity': 'ERROR',
  \     'startPosition': {
  \       'character': 14,
  \       'line': 0,
  \       'position': 1000
  \     }
  \   },
  \   {
  \     'endPosition': {
  \       'character': 11,
  \       'line': 2,
  \       'position': 1000
  \     },
  \     'failure': 'Something else',
  \     'fix': {
  \       'innerLength': 0,
  \       'innerStart': 14,
  \       'innerText': ';'
  \     },
  \     'name': 'app/test.ts',
  \     'ruleName': 'something',
  \     'ruleSeverity': 'WARNING',
  \     'startPosition': {
  \       'character': 7,
  \       'line': 1,
  \       'position': 1000
  \     }
  \   },
  \   {
  \     'endPosition': {
  \       'character': 11,
  \       'line': 2,
  \       'position': 22
  \     },
  \     'failure': 'Something else',
  \     'fix': {
  \       'innerLength': 0,
  \       'innerStart': 14,
  \       'innerText': ';'
  \     },
  \     'name': 'app/something-else.ts',
  \     'ruleName': 'something',
  \     'ruleSeverity': 'WARNING',
  \     'startPosition': {
  \       'character': 7,
  \       'line': 1,
  \       'position': 14
  \     }
  \   },
  \   {
  \     "endPosition": {
  \       "character": 19,
  \       "line": 30,
  \       "position": 14590
  \     },
  \     "failure": "Calls to console.log are not allowed.",
  \     'name': 'app/test.ts',
  \     "ruleName": "no-console",
  \     "startPosition": {
  \       "character": 8,
  \       "line": 30,
  \       "position": 14579
  \     }
  \   },
  \])])