How to Unit Test ASP.NET CORE controller with MSTEST and add Fakes

I have an MVC project in ASP.NET CORE. I have added a class library and added testing frameworks in project.json. The test methods seems to execute and run.. but i have scenarios where i need to use shims and stubs.. For example Web Client or a an interface method. I am unable to add fakes for dll's in ASP.NET CORE.. How do i do it? Is there any method to shim methods like Web client in core?

Dependencies added: "dependencies": { "NETStandard.Library": "1.6.0", "dotnet-test-mstest": "1.0.1-preview", "MSTest.TestFramework": "1.0.0-preview" },