If you really need to receive a test email, you can always use @mailinator.com (just make sure it's not sensitive info). Mailinator is a disposable, publicly viewable email address mostly useful for one-time account registrations, especially in cases where you fear they might spam you.
In recent years, I started using the + notation at gmail -- anything you put after the + and before the @ is ignored by gmail, BUT you still receive it -- the handy part is you can filter it out (e.g. myname+hackernews@gmail.com will go to myname@gmail.com, and I create a filter to archive everything that comes to myname+hackernews@gmail.com)
The "+" trick is great, except for sites that use hair-brained email "validation" scripts which reject the address. Sadly enough, these are often the ones that I most want to use the "+" for (its a great way to also keep track of who hands out your email address to spammers).
In recent years, I started using the + notation at gmail -- anything you put after the + and before the @ is ignored by gmail, BUT you still receive it -- the handy part is you can filter it out (e.g. myname+hackernews@gmail.com will go to myname@gmail.com, and I create a filter to archive everything that comes to myname+hackernews@gmail.com)