<!doctype html>
<meta charset=utf-8>
<title>Test the IIRFilterNode Interface</title>
<script src=/resources/testharness.js></script>
<script src=/resources/testharnessreport.js></script>
<script>
test(function(t) {
  var ac = new AudioContext();

  function check_args(arg1, arg2, err, desc) {
    test(function() {
      assert_throws(err, function() {
        ac.createIIRFilter(arg1, arg2)
      })
    }, desc)
  }

  check_args([], [1.0], 'NotSupportedError',
             'feedforward coefficients can not be empty');

  check_args([1.0], [], 'NotSupportedError',
             'feedback coefficients can not be empty');

  var coeff = new Float32Array(21)
  coeff[0] = 1.0;

  check_args(coeff, [1.0], 'NotSupportedError',
             'more than 20 feedforward coefficients can not be used');

  check_args([1.0], coeff, 'NotSupportedError',
             'more than 20 feedback coefficients can not be used');

  check_args([0.0, 0.0], [1.0], 'InvalidStateError',
             'at least one feedforward coefficient must be non-zero');

  check_args([0.5, 0.5], [0.0], 'InvalidStateError',
             'the first feedback coefficient must be non-zero');

}, "IIRFilterNode coefficients are checked properly");

test(function(t) {
  var ac = new AudioContext();

  var frequencies = new Float32Array([-1.0, ac.sampleRate*0.5 - 1.0, ac.sampleRate]);
  var magResults = new Float32Array(3);
  var phaseResults = new Float32Array(3);

  var filter = ac.createIIRFilter([0.5, 0.5], [1.0]);
  filter.getFrequencyResponse(frequencies, magResults, phaseResults);

  assert_true(isNaN(magResults[0]), "Invalid input frequency should give NaN magnitude response");
  assert_true(!isNaN(magResults[1]), "Valid input frequency should not give NaN magnitude response");
  assert_true(isNaN(magResults[2]), "Invalid input frequency should give NaN magnitude response");
  assert_true(isNaN(phaseResults[0]), "Invalid input frequency should give NaN phase response");
  assert_true(!isNaN(phaseResults[1]), "Valid input frequency should not give NaN phase response");
  assert_true(isNaN(phaseResults[2]), "Invalid input frequency should give NaN phase response");

}, "IIRFilterNode getFrequencyResponse handles invalid frequencies properly");
</script>