Before:
  Save g:ale_buffer_info
  Save g:ale_set_signs
  Save g:ale_set_lists_synchronously
  Save g:ale_run_synchronously

  let g:ale_set_signs = 1
  let g:ale_set_lists_synchronously = 1
  let g:ale_run_synchronously = 1

  unlet! b:ale_enabled

  let g:ale_buffer_info = {}
  let g:expected_loclist = [{
  \ 'bufnr': bufnr('%'),
  \ 'lnum': 2,
  \ 'vcol': 0,
  \ 'col': 3,
  \ 'text': 'foo bar',
  \ 'type': 'E',
  \ 'nr': -1,
  \ 'pattern': '',
  \ 'valid': 1,
  \}]
  let g:expected_groups = [
  \ 'ALECleanupGroup',
  \ 'ALECursorGroup',
  \ 'ALEHighlightBufferGroup',
  \ 'ALERunOnEnterGroup',
  \ 'ALERunOnFiletypeChangeGroup',
  \ 'ALERunOnSaveGroup',
  \ 'ALERunOnTextChangedGroup',
  \]

  function! ToggleTestCallback(buffer, output)
    return [{
    \ 'bufnr': a:buffer,
    \ 'lnum': 2,
    \ 'vcol': 0,
    \ 'col': 3,
    \ 'text': 'foo bar',
    \ 'type': 'E',
    \ 'nr': -1,
    \}]
  endfunction

  function! ParseAuGroups()
    redir => l:output
       silent exec 'autocmd'
    redir end

    let l:results = []

    for l:line in split(l:output, "\n")
      let l:match = matchlist(l:line, '^ALE[a-zA-Z]\+Group')

      " We don't care about some groups here.
      if !empty(l:match)
      \&& l:match[0] !=# 'ALECompletionGroup'
      \&& l:match[0] !=# 'ALEBufferFixGroup'
      \&& l:match[0] !=# 'ALEPatternOptionsGroup'
        call add(l:results, l:match[0])
      endif
    endfor

    call uniq(sort(l:results))

    return l:results
  endfunction

  call ale#linter#Define('foobar', {
  \ 'name': 'testlinter',
  \ 'callback': 'ToggleTestCallback',
  \ 'executable': has('win32') ? 'cmd' : 'echo',
  \ 'command': 'echo',
  \ 'read_buffer': 0,
  \})

  sign unplace *

After:
  Restore

  unlet! g:expected_loclist
  unlet! g:expected_groups
  unlet! b:ale_enabled
  unlet! g:output

  call ale#linter#Reset()

  " Toggle ALE back on if we fail when it's disabled.
  if !g:ale_enabled
    ALEToggle
  endif

  delfunction ToggleTestCallback
  delfunction ParseAuGroups

  call setloclist(0, [])
  sign unplace *
  call clearmatches()

Given foobar (Some imaginary filetype):
  foo
  bar
  baz

Execute(ALEToggle should reset everything and then run again):
  " Run this test asynchrously.
  let g:ale_run_synchronously = 0

  AssertEqual 'foobar', &filetype

  call ale#Lint()
  call ale#engine#WaitForJobs(2000)

  " First check that everything is there...
  AssertEqual g:expected_loclist, getloclist(0)
  AssertEqual [0, [[2, 1000001, 'ALEErrorSign']]], ale#sign#FindCurrentSigns(bufnr('%'))
  AssertEqual
  \ [{'group': 'ALEError', 'pos1': [2, 3, 1]}],
  \ map(getmatches(), '{''group'': v:val.group, ''pos1'': v:val.pos1}')
  AssertEqual g:expected_groups, ParseAuGroups()
  AssertEqual [{'lnum': 2, 'bufnr': bufnr(''), 'col': 3, 'linter_name': 'testlinter', 'vcol': 0, 'nr': -1, 'type': 'E', 'text': 'foo bar', 'sign_id': 1000001}], g:ale_buffer_info[bufnr('')].loclist

  " Now Toggle ALE off.
  ALEToggle

  " Everything should be cleared.
  Assert !has_key(g:ale_buffer_info, bufnr('')), 'The g:ale_buffer_info Dictionary was not removed'
  AssertEqual [], getloclist(0), 'The loclist was not cleared'
  AssertEqual [0, []], ale#sign#FindCurrentSigns(bufnr('%')), 'The signs were not cleared'
  AssertEqual [], getmatches(), 'The highlights were not cleared'
  AssertEqual ['ALECleanupGroup', 'ALEHighlightBufferGroup'], ParseAuGroups()

  " Toggle ALE on, everything should be set up and run again.
  ALEToggle
  call ale#engine#WaitForJobs(2000)

  AssertEqual g:expected_loclist, getloclist(0)
  AssertEqual [0, [[2, 1000001, 'ALEErrorSign']]], ale#sign#FindCurrentSigns(bufnr('%'))
  AssertEqual
  \ [{'group': 'ALEError', 'pos1': [2, 3, 1]}],
  \ map(getmatches(), '{''group'': v:val.group, ''pos1'': v:val.pos1}')
  AssertEqual g:expected_groups, ParseAuGroups()
  AssertEqual [{'lnum': 2, 'bufnr': bufnr(''), 'col': 3, 'linter_name': 'testlinter', 'vcol': 0, 'nr': -1, 'type': 'E', 'text': 'foo bar', 'sign_id': 1000001}], g:ale_buffer_info[bufnr('')].loclist

Execute(ALEToggle should skip filename keys and preserve them):
  " Run this test asynchrously.
  let g:ale_run_synchronously = 0

  AssertEqual 'foobar', &filetype

  let g:ale_buffer_info['/foo/bar/baz.txt'] = {
  \ 'job_list': [],
  \ 'active_linter_list': [],
  \ 'loclist': [],
  \ 'temporary_file_list': [],
  \ 'temporary_directory_list': [],
  \ 'history': [],
  \}

  call ale#Lint()
  call ale#engine#WaitForJobs(2000)

  " Now Toggle ALE off.
  ALEToggle

  AssertEqual
  \ {
  \   'job_list': [],
  \   'active_linter_list': [],
  \   'loclist': [],
  \   'temporary_file_list': [],
  \   'temporary_directory_list': [],
  \   'history': [],
  \ },
  \ get(g:ale_buffer_info, '/foo/bar/baz.txt', {})

  " Toggle ALE on again.
  ALEToggle
  call ale#engine#WaitForJobs(2000)

  AssertEqual
  \ {
  \   'job_list': [],
  \   'active_linter_list': [],
  \   'loclist': [],
  \   'temporary_file_list': [],
  \   'temporary_directory_list': [],
  \   'history': [],
  \ },
  \ get(g:ale_buffer_info, '/foo/bar/baz.txt', {})

Execute(ALEDisable should reset everything and stay disabled):
  call ale#Lint()

  AssertEqual g:expected_loclist, getloclist(0)

  ALEDisable

  AssertEqual [], getloclist(0)
  AssertEqual 0, g:ale_enabled

  ALEDisable

  AssertEqual [], getloclist(0)
  AssertEqual 0, g:ale_enabled

Execute(ALEEnable should enable ALE and lint again):
  let g:ale_enabled = 0

  ALEEnable

  AssertEqual g:expected_loclist, getloclist(0)
  AssertEqual 1, g:ale_enabled

Execute(ALEToggleBuffer should reset everything and then run again):
  " Run this test asynchrously.
  let g:ale_run_synchronously = 0

  AssertEqual 'foobar', &filetype

  call ale#Lint()
  call ale#engine#WaitForJobs(2000)

  " First check that everything is there...
  AssertEqual g:expected_loclist, getloclist(0)
  AssertEqual [0, [[2, 1000001, 'ALEErrorSign']]], ale#sign#FindCurrentSigns(bufnr('%'))
  AssertEqual
  \ [{'group': 'ALEError', 'pos1': [2, 3, 1]}],
  \ map(getmatches(), '{''group'': v:val.group, ''pos1'': v:val.pos1}')
  AssertEqual [{'lnum': 2, 'bufnr': bufnr(''), 'col': 3, 'linter_name': 'testlinter', 'vcol': 0, 'nr': -1, 'type': 'E', 'text': 'foo bar', 'sign_id': 1000001}], g:ale_buffer_info[bufnr('')].loclist

  " Now Toggle ALE off.
  ALEToggleBuffer

  " Everything should be cleared.
  Assert !has_key(g:ale_buffer_info, bufnr('')), 'The g:ale_buffer_info Dictionary was not removed'
  AssertEqual [], getloclist(0), 'The loclist was not cleared'
  AssertEqual [0, []], ale#sign#FindCurrentSigns(bufnr('%')), 'The signs were not cleared'
  AssertEqual [], getmatches(), 'The highlights were not cleared'

  " Toggle ALE on, everything should be set up and run again.
  ALEToggleBuffer
  call ale#engine#WaitForJobs(2000)

  AssertEqual g:expected_loclist, getloclist(0)
  AssertEqual [0, [[2, 1000001, 'ALEErrorSign']]], ale#sign#FindCurrentSigns(bufnr('%'))
  AssertEqual
  \ [{'group': 'ALEError', 'pos1': [2, 3, 1]}],
  \ map(getmatches(), '{''group'': v:val.group, ''pos1'': v:val.pos1}')
  AssertEqual g:expected_groups, ParseAuGroups()
  AssertEqual [{'lnum': 2, 'bufnr': bufnr(''), 'col': 3, 'linter_name': 'testlinter', 'vcol': 0, 'nr': -1, 'type': 'E', 'text': 'foo bar', 'sign_id': 1000001}], g:ale_buffer_info[bufnr('')].loclist

Execute(ALEDisableBuffer should reset everything and stay disabled):
  call ale#Lint()

  AssertEqual g:expected_loclist, getloclist(0)

  ALEDisableBuffer

  AssertEqual [], getloclist(0)
  AssertEqual 0, b:ale_enabled

Execute(ALEEnableBuffer should enable ALE and lint again):
  let b:ale_enabled = 0

  ALEEnableBuffer

  AssertEqual g:expected_loclist, getloclist(0)
  AssertEqual 1, b:ale_enabled

Execute(ALEEnableBuffer should complain when ALE is disabled globally):
  let g:ale_enabled = 0
  let b:ale_enabled = 0

  redir => g:output
    ALEEnableBuffer
  redir END

  AssertEqual [], getloclist(0)
  AssertEqual 0, b:ale_enabled
  AssertEqual 0, g:ale_enabled
  AssertEqual
  \ 'ALE cannot be enabled locally when disabled globally',
  \ join(split(g:output))