Before: Save g:ale_go_go_executable Save g:ale_go_go111module " Use an invalid global executable, so we don't match it. let g:ale_go_go_executable = 'xxxinvalid' let g:ale_go_go111module = '' call ale#test#SetDirectory('/testplugin/test/fixers') After: Restore unlet! b:ale_go_go111module call ale#test#RestoreDirectory() Execute(The gomod callback should return the correct default values): call ale#test#SetFilename('../test-files/go/go.mod') setl filetype=gomod AssertEqual \ { \ 'read_temporary_file': 1, \ 'command': ale#Escape('xxxinvalid') \ . ' mod edit -fmt' \ . ' %t', \ }, \ ale#fixers#gomod#Fix(bufnr('')) Execute(The gomod callback should support Go environment variables): call ale#test#SetFilename('../test-files/go/go.mod') setl filetype=gomod let g:ale_go_go111module = 'on' AssertEqual \ { \ 'read_temporary_file': 1, \ 'command': ale#Env('GO111MODULE', 'on') \ . ale#Escape('xxxinvalid') . ' mod edit -fmt %t' \ }, \ ale#fixers#gomod#Fix(bufnr(''))