Before: Save g:ale_toml_tombi_executable Save g:ale_toml_tombi_format_options Save g:ale_toml_tombi_online " Use an invalid global executable, so we don't match it. let g:ale_toml_tombi_executable = 'xxxinvalid' let g:ale_toml_tombi_format_options = '' call ale#test#SetDirectory('/testplugin/test/fixers') After: Restore call ale#test#RestoreDirectory() Execute(The tombi format callback should return the correct default values): AssertEqual \ {'command': ale#Escape('xxxinvalid') . ' format --offline'}, \ ale#fixers#tombi_format#Fix(bufnr('')) Execute(The tombi format callback should obey `toml_tombi_online`): let g:ale_toml_tombi_online = 1 AssertEqual \ {'command': ale#Escape('xxxinvalid') . ' lint'}, \ ale#fixers#tombi_lint#Fix(bufnr('')) Execute(The tombi format callback should include custom options): let g:ale_toml_tombi_format_options = "--no-cache" AssertEqual \ {'command': ale#Escape('xxxinvalid') . ' format --offline --no-cache'}, \ ale#fixers#tombi_format#Fix(bufnr(''))