Before:
  call ale#assert#SetUpLinterTest('sass', 'sasslint')
  call ale#test#SetFilename('test.sass')

After:
  call ale#assert#TearDownLinterTest()

Execute(The default sasslint command should be correct):
  AssertLinter 'sass-lint',
  \ 'cd ' . ale#Escape(expand('%:p:h')) . ' && '
  \   . ale#Escape('sass-lint') . ' -v -q -f compact %t'