[Test] enable precompiled headers

- also remove unused headers

src/Mod/Test/Gui/UnitTestImp.cpp

@@ -20,24 +20,20 @@
  *                                                                         *
  ***************************************************************************/
 
-
 #include "PreCompiled.h"
 #ifndef _PreComp_
 # include <QMessageBox>
-# include <QStyleFactory>
 #endif
 
-#include <Base/PyObjectBase.h>
 #include <Base/Interpreter.h>
 #include <Gui/MainWindow.h>
+
 #include "UnitTestImp.h"
 #include "ui_UnitTest.h"
-#include "UnitTestPy.h"
 
 
 using namespace TestGui;
 
-
 /* TRANSLATOR TestGui::UnitTestDialog */
 
 UnitTestDialog* UnitTestDialog::_instance=nullptr;