Before:
  call ale#assert#SetUpLinterTest('d', 'dls')

  Save &filetype
  let &filetype = 'd'

After:
  call ale#assert#TearDownLinterTest()

Execute(The language string should be correct):
  AssertLSPLanguage 'd'

Execute(The default executable should be correct):
  AssertLinter 'dls', 'dls'

Execute(The executable should be configurable):
  let g:ale_d_dls_executable = 'foobar'

  AssertLinter 'foobar', 'foobar'