Execute(The statix handler should handle statix output):
  call ale#test#SetFilename('flake.nix')

  AssertEqual
  \ [
  \   {
  \     'lnum': 46,
  \     'type': 'W',
  \     'col': 13,
  \     'code': '3',
  \     'text': 'This assignment is better written with `inherit`'
  \   },
  \ ],
  \ ale#handlers#statix#Handle(bufnr(''),
  \   '<stdin>>46:13:W:3:This assignment is better written with `inherit`'
  \)