Before:
  Save g:ale_dhall_executable
  Save g:ale_dhall_options

  " Use an invalid global executable, so we don’t match it.
  let g:ale_dhall_executable = 'odd-dhall'
  let g:ale_dhall_options = '--ascii'

  call ale#assert#SetUpFixerTest('dhall', 'dhall-format')

After:
  call ale#assert#TearDownFixerTest()

Execute(The dhall-format callback should return the correct options):
  call ale#test#SetFilename('../dhall_files/testfile.dhall')

  AssertFixer
  \ {
  \   'command': ale#Escape('odd-dhall')
  \       . ' --ascii'
  \       . ' format'
  \ }