svoid test_RenderFrequencySample_SquareWave() {
  var c = complex(0, 1);
  print(angle := c.angle()/twoPi());
  
  var renderer = RenderFrequencySample_SquareWave();

  new L<Double> l;
  for (frac : countIterator(0.0, 1.0, 0.05))
    print(frac + " = " + addAndReturn(l, renderer.get(c, frac)));
  //copyTextToClipboard(new ToJava().get(l));
  
  assertEqualsVerbose(ll(1.0, 1.0, 1.0, 1.0, 1.0, -1.0, -1.0, -1.0, -1.0, -1.0, -1.0, -1.0, -1.0, -1.0, -1.0, 1.0, 1.0, 1.0, 1.0, 1.0),
    l);
    
  new AudioAdder adder;
  renderer.subtractPeriodFrom(adder, doubleRange(0.0, 20.0), c);
  printStruct(adder);
  for i over l:
    assertEqualsVerbose(str(i), -l.get(i), adder.sampleSum(0, i, i+1));
}