Execute(ale#Env should produce the correct syntax):
  if has('win32')
    AssertEqual 'set name=xxx && ', ale#Env('name', 'xxx')
    AssertEqual 'set name="foo bar" && ', ale#Env('name', 'foo bar')
  else
    AssertEqual 'name=''xxx'' ', ale#Env('name', 'xxx')
    AssertEqual 'name=''foo bar'' ', ale#Env('name', 'foo bar')
  endif