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', \ ale#path#CdString(ale#Escape(expand('%:p:h'))) \ . ale#Escape('sass-lint') . ' -v -q -f compact %t'