Before:
  let g:ale_floating_preview = 0
  let g:ale_hover_to_floating_preview = 0
  let g:ale_detail_to_floating_preview = 0

  runtime autoload/ale/floating_preview.vim

  let g:floated_lines = []
  let g:floating_preview_show_called = 0

  " Stub out so we can track the call
  function! ale#floating_preview#Show(lines, ...) abort
    let g:floating_preview_show_called = 1
    let g:floated_lines = a:lines
  endfunction

  let g:ale_buffer_info = {
  \ bufnr('%'): {
  \   'loclist': [
  \     {
  \       'lnum': 1,
  \       'col': 10,
  \       'bufnr': bufnr('%'),
  \       'vcol': 0,
  \       'linter_name': 'notalinter',
  \       'nr': -1,
  \       'type': 'E',
  \       'code': 'semi',
  \       'text': "Missing semicolon.\r",
  \       'detail': "Every statement should end with a semicolon\nsecond line",
  \     },
  \   ],
  \ }
  \}

  call ale#linter#Reset()
  call ale#linter#PreventLoading('javascript')

After:
  Restore

  let g:ale_floating_preview = 0
  let g:ale_hover_to_floating_preview = 0
  let g:ale_detail_to_floating_preview = 0

  call cursor(1, 1)

  let g:ale_buffer_info = {}

  " Close the preview window if it's open.
  if &filetype is# 'ale-preview'
    noautocmd :q!
  endif

  call ale#linter#Reset()


Given javascript(A file with warnings/errors):
  var x = 3 + 12345678
  var x = 5*2 + parseInt("10");
  // comment

Execute(Floating preview is used with ALEDetail when g:ale_floating_preview set):
  let g:ale_floating_preview = 1

  call cursor(1, 10)

  ALEDetail

  let expected = ["Every statement should end with a semicolon", "second line"]

  AssertEqual 1, g:floating_preview_show_called
  AssertEqual expected, g:floated_lines

Execute(Floating preview is used with ALEDetail when g:ale_detail_to_floating_preview set):
  let g:ale_detail_to_floating_preview = 1

  call cursor(1, 10)

  ALEDetail

  let expected = ["Every statement should end with a semicolon", "second line"]

  AssertEqual 1, g:floating_preview_show_called
  AssertEqual expected, g:floated_lines

Execute(Floating preview is not used with ALEDetail by default):
  call cursor(1, 10)

  ALEDetail

  AssertEqual 0, g:floating_preview_show_called