Make every test set filenames and switch directories in the same way, and fix some missing escaping for the rubocop linter

test/test_foodcritic_command_callback.vader

@@ -2,25 +2,17 @@ Before:
   let g:ale_chef_foodcritic_options = '-t ~F011'
   let g:ale_chef_foodcritic_executable = 'foodcritic'
 
-  silent! cd /testplugin/test
-  let g:dir = getcwd()
-
+  call ale#test#SetDirectory('/testplugin/test')
   runtime ale_linters/chef/foodcritic.vim
 
 After:
   let g:ale_chef_foodcritic_options = ''
   let g:ale_chef_foodcritic_executable = ''
 
-  silent execute 'cd ' . g:dir
-  unlet! g:dir
-
+  call ale#test#RestoreDirectory()
   call ale#linter#Reset()
 
 Execute(command line should be assembled correctly):
-
   AssertEqual
   \ 'foodcritic -t \~F011 %t',
   \ ale_linters#chef#foodcritic#GetCommand(bufnr(''))
-
-  :q
-