nginx.conf错误提示nginx: [emerg] unknown "server_name="xx"" variable --缺少空格

当我配置完nginx.conf后，执行 /usr/local/nginx1.7.11/sbin/nginx -t 检查配置文件是否正确时，提示出错:

nginx: [emerg] unknown "server_name="atstest.mytest1.com"" variable
nginx: configuration file /usr/local/nginx1.7.11/conf/nginx.conf test failed

我的nginx.conf配置如下：
server {
                listen 8080;
                server_name atstest.mytest1.com atstest.mytest1.com.cn;
                if ($server_name="atstest.mytest1.com"){
                rewrite ^/(.*) redirect;
                              }
                location / {
                        root  /usr/local/nginx1.7.11/html/;
                        index  index.html index.htm;
                                                }
        }

 最后找到原因，是等号前后没有空格导致，nginx语法还有点古怪，少个空格都不行，
正确写法为 ：if ($server_name = "atstest.mytest1.com"){