This test sets a specific q[ho,wo] value to 1.0 (elsewhere 0), and then a neighborhood of k around ho,wo to 1.0 (else 0.0). Also vi is set to a sinusoidal input. We also run it with fully 0 q,k. We test that the output of the nonzero q,k is only different to the zero q,k in a single point. We also check the value of this difference (as a regression test).