code: def test_pole_one(self, xp, scp):
      # Test that freqresp() doesn't fail on a system with a pole at 0.
      # integrator, pole at zero: H(s) = 1 / s
      system = scp.signal.TransferFunction([1], [1, -1], dt=0.1)
      w, H = scp.signal.dfreqresp(system, n=2)
      return w, H
  
imports: from math import sqrt, pi
  from pytest import raises
  import cupy
  from cupy import testing
  import cupyx.scipy.signal
label_desc: Use image node_id 4 for calling the Test_dfreqresp obj's underlying member method code with example usage: obj.test_pole_one(xp, scp) and returns: w,  H