Before: Save g:ale_php_hackfmt_executable Save g:ale_php_hackfmt_options " Use an invalid global executable, so we don't match it. let g:ale_php_hackfmt_executable = 'xxxinvalid' let g:ale_php_hackfmt_options = '' call ale#test#SetDirectory('/testplugin/test/fixers') After: Restore call ale#test#RestoreDirectory() Execute(The hackfmt callback should return the correct default values): call ale#test#SetFilename('../hack_files/testfile.php') AssertEqual \ { \ 'read_temporary_file': 1, \ 'command': ale#Escape('xxxinvalid') \ . ' -i %t', \ }, \ ale#fixers#hackfmt#Fix(bufnr('')) Execute(The hackfmt callback should include custom hackfmt options): let g:ale_php_hackfmt_options = "--some-option" call ale#test#SetFilename('../hack_files/testfile.php') AssertEqual \ { \ 'read_temporary_file': 1, \ 'command': ale#Escape('xxxinvalid') \ . ' -i --some-option %t', \ }, \ ale#fixers#hackfmt#Fix(bufnr(''))