Cover the prettier-eslint changes with tests, and fix some problems

autoload/ale/fixers/prettier_eslint.vim

@@ -2,6 +2,15 @@
 "         w0rp <devw0rp@gmail.com>, morhetz (Pavel Pertsev) <morhetz@gmail.com>
 " Description: Integration between Prettier and ESLint.
 
+function! ale#fixers#prettier_eslint#SetOptionDefaults() abort
+    call ale#Set('javascript_prettier_eslint_executable', 'prettier-eslint')
+    call ale#Set('javascript_prettier_eslint_use_global', 0)
+    call ale#Set('javascript_prettier_eslint_options', '')
+    call ale#Set('javascript_prettier_eslint_legacy', 0)
+endfunction
+
+call ale#fixers#prettier_eslint#SetOptionDefaults()
+
 function! s:FindConfig(buffer) abort
     for l:filename in [
     \   '.eslintrc.js',
@@ -21,11 +30,6 @@ function! s:FindConfig(buffer) abort
     return ''
 endfunction
 
-call ale#Set('javascript_prettier_eslint_executable', 'prettier-eslint')
-call ale#Set('javascript_prettier_eslint_use_global', 0)
-call ale#Set('javascript_prettier_eslint_options', '')
-call ale#Set('javascript_prettier_eslint_legacy', 0)
-
 function! ale#fixers#prettier_eslint#GetExecutable(buffer) abort
     return ale#node#FindExecutable(a:buffer, 'javascript_prettier_eslint', [
     \   'node_modules/prettier-eslint-cli/dist/index.js',
@@ -33,21 +37,22 @@ function! ale#fixers#prettier_eslint#GetExecutable(buffer) abort
     \])
 endfunction
 
-function! ale#fixers#prettier_eslint#Fix(buffer, lines) abort
+function! ale#fixers#prettier_eslint#Fix(buffer) abort
     let l:options = ale#Var(a:buffer, 'javascript_prettier_eslint_options')
     let l:executable = ale#fixers#prettier_eslint#GetExecutable(a:buffer)
-    let l:config = s:FindConfig(a:buffer)
 
-    let l:eslint_config_option = ' --eslint-config-path ' . ale#Escape(l:config)
-    if ale#Var(a:buffer, 'javascript_prettier_eslint_legacy')
-      let l:eslint_config_option = ''
-    endif
+    let l:config = !ale#Var(a:buffer, 'javascript_prettier_eslint_legacy')
+    \   ? s:FindConfig(a:buffer)
+    \   : ''
+    let l:eslint_config_option = !empty(l:config)
+    \   ? ' --eslint-config-path ' . ale#Escape(l:config)
+    \   : ''
 
     return {
     \   'command': ale#Escape(l:executable)
     \       . ' %t'
     \       . l:eslint_config_option
-    \       . ' ' . l:options
+    \       . (!empty(l:options) ? ' ' . l:options : '')
     \       . ' --write',
     \   'read_temporary_file': 1,
     \}

test/fixers/test_prettier_eslint_fixer.callback.vader

@@ -0,0 +1,76 @@
+Before:
+  call ale#test#SetDirectory('/testplugin/test/fixers')
+
+  Save g:ale_javascript_prettier_eslint_executable
+  Save g:ale_javascript_prettier_eslint_use_global
+  Save g:ale_javascript_prettier_eslint_options
+  Save g:ale_javascript_prettier_eslint_legacy
+
+  unlet! g:ale_javascript_prettier_eslint_executable
+  unlet! g:ale_javascript_prettier_eslint_use_global
+  unlet! g:ale_javascript_prettier_eslint_options
+  unlet! g:ale_javascript_prettier_eslint_legacy
+
+  call ale#fixers#prettier_eslint#SetOptionDefaults()
+
+After:
+  Restore
+
+  unlet! b:ale_javascript_prettier_eslint_executable
+  unlet! b:ale_javascript_prettier_eslint_use_global
+  unlet! b:ale_javascript_prettier_eslint_options
+  unlet! b:ale_javascript_prettier_eslint_legacy
+
+  call ale#test#RestoreDirectory()
+
+Execute(The default command should be correct):
+  AssertEqual
+  \ {
+  \   'read_temporary_file': 1,
+  \   'command':
+  \     ale#Escape('prettier-eslint')
+  \     . ' %t'
+  \     . ' --write'
+  \ },
+  \ ale#fixers#prettier_eslint#Fix(bufnr(''))
+
+Execute(Additional options should be used when set):
+  let b:ale_javascript_prettier_eslint_options = '--foobar'
+
+  AssertEqual
+  \ {
+  \   'read_temporary_file': 1,
+  \   'command':
+  \     ale#Escape('prettier-eslint')
+  \     . ' %t'
+  \     . ' --foobar --write'
+  \ },
+  \ ale#fixers#prettier_eslint#Fix(bufnr(''))
+
+Execute(Configuration files should be detected):
+  call ale#test#SetFilename('eslint-test-files/react-app/foo/bar.js')
+
+  AssertEqual
+  \ {
+  \   'read_temporary_file': 1,
+  \   'command':
+  \     ale#Escape('prettier-eslint')
+  \     . ' %t'
+  \     . ' --eslint-config-path ' . ale#Escape(g:dir . '/eslint-test-files/react-app/.eslintrc.js')
+  \     . ' --write'
+  \ },
+  \ ale#fixers#prettier_eslint#Fix(bufnr(''))
+
+Execute(Configuration files should be disabled if the legacy option is on):
+  call ale#test#SetFilename('eslint-test-files/react-app/foo/bar.js')
+  let b:ale_javascript_prettier_eslint_legacy = 1
+
+  AssertEqual
+  \ {
+  \   'read_temporary_file': 1,
+  \   'command':
+  \     ale#Escape('prettier-eslint')
+  \     . ' %t'
+  \     . ' --write'
+  \ },
+  \ ale#fixers#prettier_eslint#Fix(bufnr(''))