Before: call ale#test#SetDirectory('/testplugin/test/fixers') After: Restore call ale#test#RestoreDirectory() Execute(The hindent callback should return the correct default values): call ale#test#SetFilename('../haskell_files/testfile.hs') AssertEqual \ { \ 'read_temporary_file': 1, \ 'command': ale#Escape('hindent') \ . ' %t', \ }, \ ale#fixers#hindent#Fix(bufnr(''))