After:
  unlet! g:output

Execute(ALEInfo -clipboard should tell the user that clipboard support is required):
  " When run in the Docker image, there's no clipboard support, so this test
  " will actually run.
  if !has('clipboard')
    let g:output = ''

    redir => g:output
      :ALEInfo -clipboard
    redir END

    AssertEqual 'clipboard not available. Try :ALEInfoToFile instead.', join(split(g:output))
  endif