void TestRooFit(const Int_t nfits=1)
{
    TH1F *h=new TH1F("h","",100,-10,10);
    RooRealVar x("x","x",-10,10);
    RooRealVar s("s","s",1,-10,10);
    RooRealVar m("m","m",0,-10,10);
    RooGaussian g("gauss","gauss(x,m,s)",x,m,s);
    RooPlot *f=x.frame();

    for (Int_t i=0; i<nfits; i++) {

        for (Int_t j=0; j<1000; j++) {
           h->Fill(gRandom->Gaus(0,2));
        }

        RooDataHist d("d","",x,h);

        g.fitTo(d);
        d.plotOn(f);
        g.plotOn(f);

        f->Clear();
        h->Reset();
    }
}