* Fixed the unit tests so that they are now passing.
Note: This is my first real introduction to Moq, so there are probably a few things that can be improved.
Changes:
* Had a few issues with the mock logger, ended up adding a LoggerFactory and Logger implementation to work around this issue (for some reason the mock logger was never called and the unit tests failed because the string builder was never updated).
* Accommodated changes to the SignInManager, UserManager where the latest version has added Logging to constructor
* SecurityStamp functions in UserManager now check for null and throws an exception, so the unit tests can no longer call GetSecurityStampAsync before its set. Line 866: https://github.com/dotnet/aspnetcore/blame/605c522fa3e875fd6d3aefa783a71d1745b7e4c7/src/Identity/Extensions.Core/src/UserManager.cs
* SignInManager.RefreshSignInAsync has changed the internal method from s.SignInAsync to SignInWithClaimsAsync
David Barker