How to run all web tests by command line

I have dedicated DLL project for webtests. I know how to run specified webtest

C:\Program Files (x86)\Microsoft Visual Studio 12.0\Common7\IDE>mstest /testcont
ainer:"MyPath\PostAccessToken.webtest" /resultsfile:MyResultPath\MyResults.trx

But how can I run all webtests from this library by one command? If I give DLL path as testcontainer then I get message "no tests found"