Unable to add the Grain Runtime in Unit test cases

Question

I am trying to unit test my custom grain and in doing that Grain constructor is throwing null reference exception at Runtime.Context.

Tried scenarios:

• Using the test cluster reference from following docs: https://learn.microsoft.com/en-us/dotnet/orleans/implementation/testing
• Mocking the Grains https://sergeybykov.github.io/orleans/1.5/Tutorials/Unit-Testing-Grains.html

For the point 2, GrainFactory is coming null, tried adding public and virtual so as to mock but still throwing error:

public new virtual IGrainFactory GrainFactory  
{  
get =\> base.GrainFactory;  
}