anchor.diff:      | x when x < 0 -> FatalError "FatalError"
       | _ -> TestsFailed
   
  -/// Run NUnit on a group of assemblies.
  +/// Runs NUnit on a group of assemblies.
  +/// ## Parameters
  +/// 
  +///  - `setParams` - Function used to manipulate the default NUnitParams value.
  +///  - `assemblies` - Sequence of one or more assemblies containing NUnit unit tests.
  +/// 
  +/// ## Sample usage
  +///
  +///     Target "Test" (fun _ ->
  +///         !! (testDir + @"\Test.*.dll") 
  +///           |> NUnit (fun p -> { p with ErrorLevel = DontFailBuild })
  +///     )
   let NUnit setParams (assemblies: string seq) =
       let details = assemblies |> separated ", "
       traceStartTask "NUnit" details
  
positive.code:         | OK -> traceEndTask "NUnit" details
          | _ -> failwith (errorDescription result)
  
  type NUnitParallelResult =
      {
          AssemblyName : string
          ErrorOut : StringBuilder
          StandardOut : StringBuilder
          ReturnCode : int
          OutputFile : string
      }
  
  let NUnitParallel setParams (assemblies: string seq) =
      let details = assemblies |> separated ", "
      traceStartTask "NUnitParallel" details
  
negative.code:     if hasFailed then          
          failwith "NUnitParallel test runs failed."
      else
          traceEndTask "NUnitParallel" details