Added some missing tests for ADAL::AuthenticationContext.
Added some missing tests for ADAL::AuthenticationContext.

AzureAD/azure-activedirectory-library-for-ruby,AzureAD/azure-activedirectory-library-for-ruby,cosmincojocar/azure-activedirectory-library-for-ruby,cosmincojocar/azure-activedirectory-library-for-ruby