I currently have test project where it has feature file that has 30 test scenarios. it had been working which mean I could run the test and see the test showing up in Test Explorer, not until I made mistake to delete content in this folder "AppData\Local\Microsoft\VisualStudio\14.0\Extensions" because I thought I was deleting something from this folder "AppData\Local\Temp\VisualStudioTestExplorerExtensions" as a result it messed up my test project. So I started troubleshooting, suddenly all of my tests stop showing up in the Test Explorer.
My project installations has: NUnitTestAdapter, SpecFlow, SpecFlow.Assit.Dynamic, SpecRun.Runner, Selenium.Support, Selenium.WebDriver, NUnit, Selenium.StandardControls.
My Visual Studio is Community 2015.
Also I purchased SpecRun license as well.