void generate_test() {
	//Setting up RooFit
	gSystem->Load("libRooFit");
	using namespace RooFit;

	//Open histos file
	TFile *dTR= new TFile("Test_RooFit_D.root");
	TFile *eTR= new TFile("Test_RooFit_E.root");
    
    TCanvas *c1= new TCanvas;
	TH1D* imass_D_mb,*imass_D_elec,*imass_D_mb_ss,*imass_D_elec_ss;
	TH1D* imass_E_mb,*imass_E_elec,*imass_E_mb_ss,*imass_E_elec_ss;
	TH1D* imass_D_mb_cont, *hbkg;
	RooPlot *frame;
	RooDataHist *mbshape, *mbbkg, *hsignal;

	//Build the pdf
    imass_D_mb=(TH1D *)dTR->Get("Z_mass_elec_OS");
    imass_E_mb=(TH1D *)eTR->Get("Z_mass_elec_OS");
	//Needed for correct errors
    imass_D_mb->Sumw2();
    imass_E_mb->Sumw2();
	imass_D_mb->Add(imass_E_mb);
	imass_D_mb_ss=(TH1D *)dTR->Get("Z_mass_elec_SS");
	imass_E_mb_ss=(TH1D *)eTR->Get("Z_mass_elec_SS");
	imass_D_mb_ss->Sumw2();
	imass_E_mb_ss->Sumw2();
	//os-ss
	imass_D_mb_ss->Scale(-1.);
	imass_E_mb_ss->Scale(-1.);
	imass_D_mb->Add(imass_D_mb_ss);
	imass_D_mb->Add(imass_E_mb_ss);
	imass_D_mb_cont=imass_D_mb;
	//Generate bkg to match s/b and save as TH1
	//Doesn't work so well - generateBinned gives back less than 250 bins...
	x = new RooRealVar("x","m_{ee} (GeV)",0.,25.);
	frame = x->frame();
	//input has 250 bins
	mbshape = new RooDataHist("mbshape", "bkg shape",RooArgList(*x),imass_D_mb_cont);
	//RooHistPdf plot looks like it has more than 250 bins
	mbpdf = new RooHistPdf("mbpdf","mbpdf",*x,*mbshape);
	//Result of generateBinned has much less than 250 bins :-(
	mbbkg = mbpdf->generateBinned(*x,100000,kTRUE);
	mbbkg->plotOn(frame, Name("data"), DataError(RooAbsData::SumW2));
	frame->Draw();
	frame->SetTitle("");
	frame->GetYaxis()->SetTitleOffset(1.2);
	//c1->Print("test_bkg_shape","eps");
	hbkg = (TH1D*)mbbkg->createHistogram("hbkg",*x,Binning(250,0.,25.));
	hbkg->Sumw2();
	hbkg->Draw();
	hbkg->GetXaxis()->SetRangeUser(1.,5.);

}