Before:
  Save g:ale_echo_cursor
  Save g:ale_fix_on_save
  Save g:ale_fixers
  Save g:ale_lint_on_save
  Save g:ale_set_highlights
  Save g:ale_set_lists_synchronously
  Save g:ale_set_loclist
  Save g:ale_set_quickfix
  Save g:ale_set_signs

  let g:ale_run_synchronously = 1
  let g:ale_set_lists_synchronously = 1
  " Disable the things we don't need, but leave enabled what we do.
  let g:ale_echo_cursor = 0
  let g:ale_set_signs = 0
  let g:ale_set_quickfix = 0
  let g:ale_set_loclist = 1
  let g:ale_set_highlights = 0
  let g:ale_echo_cursor = 0

  function! TestCallback(buffer, output)
    return [{'lnum': 1, 'col': 1, 'text': 'xxx'}]
  endfunction

  function AddLine(buffer, lines) abort
    return a:lines + ['x']
  endfunction

  let g:ale_fixers = {
  \ 'testft': ['AddLine'],
  \}

  call ale#linter#PreventLoading('testft')
  call ale#linter#Define('testft', {
  \ 'name': 'testlinter',
  \ 'callback': 'TestCallback',
  \ 'executable': has('win32') ? 'cmd' : 'true',
  \ 'command': 'true',
  \})

Given testft (An empty file):

After:
  Restore

  unlet! g:ale_run_synchronously
  unlet! b:ale_quitting
  delfunction TestCallback
  delfunction AddLine

  call ale#linter#Reset()
  call setloclist(0, [])

Execute(No linting should be done on :wq or :x):
  let g:ale_lint_on_save = 1
  let g:ale_fix_on_save = 0

  " First try just the SaveEvent, to be sure that we set errors in the test.
  call ale#events#SaveEvent(bufnr(''))
  call ale#test#FlushJobs()

  AssertEqual 1, len(ale#test#GetLoclistWithoutNewerKeys())

  " Now try doing it again, but where we run the quit event first.
  call setloclist(0, [])
  call ale#events#QuitEvent(bufnr(''))
  call ale#events#SaveEvent(bufnr(''))
  call ale#test#FlushJobs()

  AssertEqual [], ale#test#GetLoclistWithoutNewerKeys()

Execute(No linting should be for :w after :q fails):
  let g:ale_lint_on_save = 1
  let g:ale_fix_on_save = 0

  call ale#events#QuitEvent(bufnr(''))
  call ale#test#FlushJobs()

  " Simulate 2 seconds passing.
  let b:ale_quitting -= 1000

  call ale#events#SaveEvent(bufnr(''))
  call ale#test#FlushJobs()

  AssertEqual 1, len(ale#test#GetLoclistWithoutNewerKeys())

Execute(No linting should be done on :wq or :x after fixing files):
  let g:ale_lint_on_save = 1
  let g:ale_fix_on_save = 1

  call ale#events#SaveEvent(bufnr(''))
  call ale#test#FlushJobs()

  AssertEqual 1, len(ale#test#GetLoclistWithoutNewerKeys())

  " Now try doing it again, but where we run the quit event first.
  call setloclist(0, [])
  call ale#events#QuitEvent(bufnr(''))
  call ale#events#SaveEvent(bufnr(''))
  call ale#test#FlushJobs()

  AssertEqual [], ale#test#GetLoclistWithoutNewerKeys()

Execute(Linting should be done after :q fails and fixing files):
  let g:ale_lint_on_save = 1
  let g:ale_fix_on_save = 1

  call ale#events#QuitEvent(bufnr(''))
  call ale#test#FlushJobs()

  " Simulate 2 seconds passing.
  let b:ale_quitting -= 1000

  call ale#events#SaveEvent(bufnr(''))
  call ale#test#FlushJobs()

  AssertEqual 1, len(ale#test#GetLoclistWithoutNewerKeys())