如果没有安装pear先安装pear
http://pear.php.net/go-pear.phar
下载文件go-pear.phar到php安装目录下
命令行执行：php go-pear.phar
添加channel：
pear channel-discover pear.phpunit.de
pear channel-discover components.ez.no
pear channel-discover pear.symfony-project.com
然后安装PHPUnit：
pear install phpunit/PHPUnit
如果安装失败
那么我们更新一下pear就可以了：
pear channel-update pear.php.net
pear upgrade-all
再安装：
pear install phpunit/PHPUnit
来安装PHPUnit，应该就可以看到Install ok了。
如果还是不行，执行下
pear clear-cache
再安装
Error：Unknown remote channel: pear.symfony.com phpunit/PHPUnit requires package"channel://pear.symfony.com/Yaml"(version >=2.1.0)No valid packages found
解决：pear channel-discover pear.symfony.com pear install pear.symfony.com/Yaml
