Execute Unit Tests using MsBuild command line

I use scripting for this:

"%ProgramFiles%\Microsoft Visual Studio 9.0\Common7\IDE\TF.exe" 
  get $/DmlOnDemmand /recursive /force /noprompt

And I build solution .sln

call %msBuildDir%\msbuild %solutionName% /t:Rebuild /p:Configuration=%buildType%

Now, I would like execute all Unit Tests and check all is OK.

How can I execute unit tests of .csproj projects of a solution from the command line using a build tool like MSBuild?