double step = (pb.getFinalTime() - pb.getInitialTime()) * 0.001;
FirstOrderIntegrator integ = new EulerIntegrator(step);
TestProblemHandler handler = new TestProblemHandler(pb, integ);
integ.setStepHandler(handler);
integ.integrate(pb,
pb.getInitialTime(), pb.getInitialState(),
pb.getFinalTime(), new double[pb.getDimension()]);
assertTrue(handler.getLastError() < 2.0e-4);
assertTrue(handler.getMaximalValueError() < 1.0e-3);