First, read up about Writeup Formatting Tips to learn how to format your posts properly.

To address your problem:
From what I see from the docs of HTTP::WebTest it uses LWP under the hood. In the docs it says

If you want to test https:// web sites you may have to install additional modules to enable SSL support in LWP. In short you may have to install Crypt::SSLeay module. For details see README.SSL file in LWP distro.

So, as mentioned above, you don't have to take any measures, besides of installing Crypt::SSLeay. There is no special syntax. Simply use

$url="https://my.site.com/";
[download]