diff --git a/App/inc/TestBessel.h b/App/inc/TestBessel.h
new file mode 100644
index 0000000000000000000000000000000000000000..0c2037271eaa4e8d669966f349fc3e0033a1c1d8
--- /dev/null
+++ b/App/inc/TestBessel.h
@@ -0,0 +1,57 @@
+// ************************************************************************** //
+//
+//  BornAgain: simulate and fit scattering at grazing incidence
+//
+//! @file      App/inc/TestBessel.h
+//! @brief     Defines class TestBessel.
+//
+//! Homepage:  apps.jcns.fz-juelich.de/BornAgain
+//! License:   GNU General Public License v3 or higher (see COPYING)
+//! @copyright Forschungszentrum Jülich GmbH 2013
+//! @authors   Scientific Computing Group at MLZ Garching
+//! @authors   C. Durniak, G. Pospelov, W. Van Herck, J. Wuttke
+//
+// ************************************************************************** //
+
+#ifndef TESTBESSEL_H
+#define TESTBESSEL_H
+
+#include "IApplicationTest.h"
+#include "Numeric.h"
+
+class TestBessel : public IApplicationTest
+{
+public:
+
+    class Data {
+    public:
+        Data() : x(0), b1(0), b2(0) {}
+        double x;
+        double b1;
+        double b2;
+    };
+
+    TestBessel(){}
+    ~TestBessel(){}
+    virtual void execute();
+    void run_benchmark();
+
+    // (x1-x2)/x2
+    double rel_diff(double x1, double x2)
+    {
+        double ratio(0);
+        double diff = x1 - x2;
+        if( std::abs(diff) <= Numeric::double_epsilon && std::abs(x2) <= Numeric::double_epsilon) {
+            ratio = 0.0;
+        } else if(std::abs(x2) <= Numeric::double_epsilon) {
+            ratio = diff/Numeric::double_epsilon;
+        } else {
+            ratio = diff/x2;
+        }
+        return ratio;
+    }
+
+};
+
+#endif // TESTBESSEL_H
+
diff --git a/App/src/ApplicationTestFactory.cpp b/App/src/ApplicationTestFactory.cpp
index d11a1351a985e1189457335e61a012df5aeb49f6..abdcd8d2a371d27094ff3a43c841671a696ef710 100644
--- a/App/src/ApplicationTestFactory.cpp
+++ b/App/src/ApplicationTestFactory.cpp
@@ -46,6 +46,7 @@
 #include "TestFunctionalTests.h"
 #include "TestRipple2.h"
 #include "TestRipple1.h"
+#include "TestBessel.h"
 
 
 #include "TBenchmark.h"
@@ -279,6 +280,11 @@ void RegisterApplicationTests(ApplicationTestFactory *p_test_factory)
         IFactoryCreateFunction<TestRipple1, IApplicationTest>,
         "test the new ripple1 formfactor");
 
+    p_test_factory->registerItem(
+        "bessel",
+        IFactoryCreateFunction<TestBessel, IApplicationTest>,
+        "test complex bessel functions");
+
 
 }
 
diff --git a/App/src/TestBessel.cpp b/App/src/TestBessel.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..e68aa83802740dc801e6c3c83aa205e4f5d5124c
--- /dev/null
+++ b/App/src/TestBessel.cpp
@@ -0,0 +1,55 @@
+#include "TestBessel.h"
+#include "MathFunctions.h"
+#include "TCanvas.h"
+#include "TH2D.h"
+#include "TBenchmark.h"
+#include "TMath.h"
+#include <iostream>
+
+
+
+
+void TestBessel::execute()
+{
+    std::cout << "TestBessel::execute() -> Hello World" << std::endl;
+
+    double xmin(0.0), xmax(20.0);
+    int nx(201);
+    double dx = (xmax-xmin)/(nx-1);
+
+    std::cout << "dx: " << dx << std::endl;
+
+    std::vector<Data> buff;
+    buff.resize(nx);
+
+    for(int i=0; i<nx; ++i) {
+        double x = xmin + dx*i;
+        buff[i].x = x;
+        buff[i].b1 = TMath::BesselJ1(x);
+        buff[i].b2 = MathFunctions::Bessel_J1(x);
+
+        std::cout << i << " " << x << " " << buff[i].b1 << std::endl;
+    }
+
+
+    TCanvas *c1 = new TCanvas("c1","c1",1024, 768);
+    TH1D *h2 = new TH1D("h2","h2", nx, xmin - dx/2., xmax+dx/2.);
+    for(int i=0; i<nx; ++i) {
+        h2->Fill(buff[i].x, rel_diff(buff[i].b1, buff[i].b2));
+    }
+
+    c1->Divide(2,2);
+    c1->cd(1);
+    h2->Draw();
+
+
+}
+
+
+
+void TestBessel::run_benchmark()
+{
+
+}
+
+