private void CompileFunctionalTests()
{
var sourceFiles = new FileSet().Include(directory_base.SubFolder("tests")).RecurseAllSubDirectories.Filter("*.cs");
Task.Build.Csc.Target.Library(x=>x
.AddSources(sourceFiles)
.AddRefences(thirdparty_rhino, thirdparty_nunit, assembly_FluentBuild_WithTests_Merged, assembly_FluentBuild_Runner)
.OutputFileTo(assembly_Functional_Tests));
}