all unit tests in newly added Unit Test Project are not appeared in ‘Test Explorer’
or those unit tests are marked as “Not Run Tests” and never run it no matter how hard you pressure visual studio to run.
do following two steps to fix:
delete following two framework references
Microsoft.VisualStudio.TestPlatform.TestFramework、
Microsoft.VisualStudio.TestPlatform.TestFramework.Extensions
and add Microsoft.VisualStudio.QualityTools.UnitTestFramework