Before:
  Save g:ale_enabled
  Save g:ale_set_lists_synchronously
  Save g:ale_buffer_info
  Save &shell

  let g:ale_enabled = 1
  let g:ale_buffer_info = {}
  let g:ale_set_lists_synchronously = 1

  function! TestCallback(buffer, output)
    " Windows adds extra spaces to the text from echo.
    return [{
    \ 'lnum': 2,
    \ 'col': 3,
    \ 'text': substitute(a:output[0], ' *$', '', ''),
    \}]
  endfunction
  function! TestCallback2(buffer, output)
    return [{
    \ 'lnum': 3,
    \ 'col': 4,
    \ 'text': substitute(a:output[0],  ' *$', '', ''),
    \}]
  endfunction

  " Running the command in another subshell seems to help here.
  call ale#linter#Define('foobar', {
  \ 'name': 'testlinter',
  \ 'callback': 'TestCallback',
  \ 'executable': has('win32') ? 'cmd' : 'echo',
  \ 'command': has('win32') ? 'echo foo bar' : '/bin/sh -c ''echo foo bar''',
  \})

After:
  Restore

  unlet! g:i
  unlet! g:results
  unlet! g:expected_results

  delfunction TestCallback
  delfunction TestCallback2
  call ale#engine#Cleanup(bufnr(''))
  call ale#linter#Reset()

Given foobar (Some imaginary filetype):
  foo
  bar
  baz

Execute(Linters should run with the default options):
  AssertEqual 'foobar', &filetype

  let g:expected_results = [{
  \   'bufnr': bufnr('%'),
  \   'lnum': 2,
  \   'vcol': 0,
  \   'col': 3,
  \   'text': 'foo bar',
  \   'type': 'E',
  \   'nr': -1,
  \   'pattern': '',
  \   'valid': 1,
  \ }]

  " Try the test a few times over in NeoVim 0.3 or Windows or Vim 8.2,
  " where tests fail randomly.
  for g:i in range(has('nvim-0.3') || has('win32') || has('patch-8.2.2401') ? 5 : 1)
    call ale#Queue(0, '')
    call ale#test#WaitForJobs(2000)

    let g:results = ale#test#GetLoclistWithoutNewerKeys()

    if g:results == g:expected_results
      break
    endif
  endfor

  AssertEqual g:expected_results, g:results

Execute(Linters should run in PowerShell too):
  if has('win32')
    set shell=powershell

    AssertEqual 'foobar', &filetype

    " Replace the callback to handle two lines.
    function! TestCallback(buffer, output)
      " Windows adds extra spaces to the text from echo.
      return [
      \ {
      \   'lnum': 1,
      \   'col': 3,
      \   'text': substitute(a:output[0], ' *$', '', ''),
      \ },
      \ {
      \   'lnum': 2,
      \   'col': 3,
      \   'text': substitute(a:output[1], ' *$', '', ''),
      \ },
      \]
    endfunction

    " Recreate the command string to use &&, which PowerShell does not support.
    call ale#linter#Reset()
    call ale#linter#Define('foobar', {
    \ 'name': 'testlinter',
    \ 'callback': 'TestCallback',
    \ 'executable': 'cmd',
    \ 'command': 'echo foo && echo bar',
    \})

    call ale#Queue(0, '')
    call ale#test#WaitForJobs(4000)

    AssertEqual [
    \ {
    \   'bufnr': bufnr('%'),
    \   'lnum': 1,
    \   'vcol': 0,
    \   'col': 3,
    \   'text': 'foo',
    \   'type': 'E',
    \   'nr': -1,
    \   'pattern': '',
    \   'valid': 1,
    \ },
    \ {
    \   'bufnr': bufnr('%'),
    \   'lnum': 2,
    \   'vcol': 0,
    \   'col': 3,
    \   'text': 'bar',
    \   'type': 'E',
    \   'nr': -1,
    \   'pattern': '',
    \   'valid': 1,
    \ },
    \], ale#test#GetLoclistWithoutNewerKeys()
  endif

Execute(Previous errors should be removed when linters change):
  call ale#Queue(0, '')
  call ale#test#WaitForJobs(2000)

  call ale#linter#Reset()

  call ale#linter#Define('foobar', {
  \ 'name': 'testlinter2',
  \ 'callback': 'TestCallback2',
  \ 'executable': has('win32') ? 'cmd' : 'echo',
  \ 'command': has('win32') ? 'echo baz boz' : '/bin/sh -c ''echo baz boz''',
  \})

  let g:expected_results = [{
  \ 'bufnr': bufnr('%'),
  \ 'lnum': 3,
  \ 'vcol': 0,
  \ 'col': 4,
  \ 'text': 'baz boz',
  \ 'type': 'E',
  \ 'nr': -1,
  \ 'pattern': '',
  \ 'valid': 1,
  \}]

  " Try the test a few times over in NeoVim 0.3 or VIm 8.2 or Windows,
  " where tests fail randomly.
  for g:i in range(has('nvim-0.3') || has('win32') || has('patch-8.2.2401') ? 5 : 1)
    call ale#Queue(0, '')
    call ale#test#WaitForJobs(2000)

    let g:results = ale#test#GetLoclistWithoutNewerKeys()

    if g:results == g:expected_results
      break
    endif
  endfor

  AssertEqual g:expected_results, g:results