比如unicorn的配置文件（config/unicorn.rb）中默认这样写：

listen "/tmp/myapp/unicorn.sock", backlog: 1
pid "/tmp/myapp/unicorn.pid"

要根据实际运行环境和测试环境区分开，想这样实现：

if ENV["RAILS_ENV"] == "production"
  listen "/tmp/myapp/unicorn.sock", backlog: 1
  pid "/tmp/myapp/unicorn.pid"
else
  listen "/tmp/myapp/test.sock", backlog: 1
  pid "/tmp/myapp/test.pid"
end

却不能达到目的，有没有可行方法？