anchor.diff:  /// ## Sample usage
   ///
   ///     Target "Test" (fun _ ->
  -///         !! (testDir + @"\Test.*.dll") 
  +///         !! (testDir + @"\*.Tests.dll") 
   ///           |> MSTest (fun p -> { p with Category = "group1" })
   ///     )
   let MSTest (setParams: MSTestParams -> MSTestParams) (assemblies: string seq) =
       let details = assemblies |> separated ", "
       traceStartTask "MSTest" details
  -    trace ("Hello from MSTest" @@ details)
       let parameters = MSTestDefaults |> setParams
                 
       let assemblies =  assemblies |> Seq.toArray
  -
       if Array.isEmpty assemblies then
           failwith "MSTest: cannot run tests (the assembly list is empty)."
   
  -    let tool = toolPath()
  +    let tool = 
  +        match tryFindFile mstestPaths mstestexe with
  +        | Some path -> path
  +        | None -> failwith "Cannot find MSTest.exe executable"
  +
  +    let failIfError assembly exitCode =
  +        if exitCode > 0 then
  +            let message = sprintf "%sMSTest test run failed for %s" Environment.NewLine assembly
  +            traceError message
  +            failwith message
   
       for assembly in assemblies do
           let args = commandLineBuilder parameters assembly
  -        let exitCode = execProcessAndReturnExitCode (fun info ->  
  +        execProcessAndReturnExitCode (fun info ->  
               info.FileName <- tool
               info.WorkingDirectory <- parameters.WorkingDir
               info.Arguments <- args) parameters.TimeOut
  -        trace ("exit code: " + exitCode.ToString())
  -    
  +            |> failIfError assembly
  +
       traceEndTask "MSTest" details
  
positive.code:         |> appendIfNotNull testResultsFile "/resultsfile:"
  
      cl.ToString()
  
  /// Runs MSTest command line tool on a group of assemblies.
  /// ## Parameters
  
negative.code:         "mstest.exe"
  
   // TODO: try to use VSTest.Console.exe as well (VS2012 and up only)
  
  /// Parameter type to configure the MSTest.exe
  type MSTestParams = 
  