Usability Task Involving Email Addresses

I am planning a usability test for a product and one of the product's main features is the capability to share a file with another user (Google Doc's sharing style). I wish to test this feature and as a task, I will be asking the participants what they will do if they were to share a file. I'm considering the 3 options:

  1. At first, my initial idea was to give participants a fake email address (...@example.com) to share the file with. But this doesn't seem realistic so I don't think participants will be immersed with the whole task.

  2. Provide a more realistic email address with an actual domain. But again, if the user doesn't use that domain, it won't be realistic as well. And we have to be aware of spam issues.

  3. Don't provide an email address. Participants will have to either: A) just explain to us what they will do, or B) log in to the device with their google account and fetch a contact from it. But A will affect the accuracy of the task time and not many participants will be willing to go through B.

So I wish to ask for some advice on if anyone has conducted a similar usability test and what's my best approach. The task time is very important for this test I am planning, which is something to consider. Reading this article, it seems Option 2 is the best choice but I'm wondering if there are better options out there. Thanks!