Before: call ale#test#SetDirectory('/testplugin/test/fixers') Save g:ale_javascript_prettier_executable Save g:ale_javascript_prettier_options " Use an invalid global executable, so we don't match it. let g:ale_javascript_prettier_executable = 'xxxinvalid' let g:ale_javascript_prettier_options = '' call ale#test#SetDirectory('/testplugin/test/fixers') silent cd .. silent cd command_callback let g:dir = getcwd() After: let g:ale_has_override = {} call ale#test#RestoreDirectory() call ale#semver#ResetVersionCache() Execute(The prettier callback should return the correct default values): call ale#test#SetFilename('../prettier-test-files/testfile.js') AssertEqual \ { \ 'read_temporary_file': 1, \ 'command': ale#Escape(g:ale_javascript_prettier_executable) \ . ' %t' \ . ' --write', \ }, \ ale#fixers#prettier#ApplyFixForVersion(bufnr(''), []) Execute(The --config option should not be set automatically): let g:ale_javascript_prettier_use_local_config = 1 call ale#test#SetFilename('../prettier-test-files/with_config/testfile.js') AssertEqual \ { \ 'read_temporary_file': 1, \ 'command': ale#Escape(g:ale_javascript_prettier_executable) \ . ' %t' \ . ' --write', \ }, \ ale#fixers#prettier#ApplyFixForVersion(bufnr(''), []) Execute(The prettier callback should include custom prettier options): let g:ale_javascript_prettier_options = '--no-semi' call ale#test#SetFilename('../prettier-test-files/with_config/testfile.js') AssertEqual \ { \ 'read_temporary_file': 1, \ 'command': ale#Escape(g:ale_javascript_prettier_executable) \ . ' %t' \ . ' --no-semi' \ . ' --write', \ }, \ ale#fixers#prettier#ApplyFixForVersion(bufnr(''), []) Execute(The version check should be correct): call ale#test#SetFilename('../prettier-test-files/testfile.js') AssertEqual \ { \ 'chain_with': 'ale#fixers#prettier#ApplyFixForVersion', \ 'command': ale#Escape(g:ale_javascript_prettier_executable) \ . ' --version', \ }, \ ale#fixers#prettier#Fix(bufnr('')) Execute(--stdin-filepath should be used when prettier is new enough): let g:ale_javascript_prettier_options = '--no-semi' call ale#test#SetFilename('../prettier-test-files/with_config/testfile.js') AssertEqual \ { \ 'command': 'cd ' . ale#Escape(expand('%:p:h')) . ' && ' \ . ale#Escape(g:ale_javascript_prettier_executable) \ . ' --no-semi' \ . ' --stdin-filepath %s --stdin', \ }, \ ale#fixers#prettier#ApplyFixForVersion(bufnr(''), ['1.6.0']) Execute(The version number should be cached): call ale#test#SetFilename('../prettier-test-files/with_config/testfile.js') " Call the second callback with the version output. call ale#fixers#prettier#ApplyFixForVersion(bufnr(''), ['1.6.0']) " Call it again without the version output. We should use the newer command. AssertEqual \ { \ 'command': 'cd ' . ale#Escape(expand('%:p:h')) . ' && ' \ . ale#Escape(g:ale_javascript_prettier_executable) \ . ' --stdin-filepath %s --stdin', \ }, \ ale#fixers#prettier#ApplyFixForVersion(bufnr(''), [])