Fake dll in .net core

Hi Team,

I am doing a migration asp.net project 4.5 frameworks toasp.net core 3.1.

I can see fake dll is used in 4.5 framework so this is feature of Visual studio enterprise edition inasp.net core also we can generate fake dll

so want to know is fake dll is supported in .net core?

any suggestion and help will be highly appreciated on how to proceed further on this.
Regards