<!DOCTYPE html>
<script src="../resources/testharness.js"></script>
<script src="../resources/testharnessreport.js"></script>

<script>
var EPSILON = 1e-6; // float epsilon
var values = [
  {input: new CSSSkew(0, 0), ax: 0, ay: 0, cssText: "skew(0, 0)"},
  {input: new CSSSkew(1, 2), ax: 1, ay: 2, cssText: "skew(1, 2)"},
  {input: new CSSSkew(-2, -4), ax: -2, ay: -4, cssText: "skew(-2, -4)"},
  {input: new CSSSkew(3.4, 2.7), ax: 3.4, ay: 2.7, cssText: "skew(3.4, 2.7)"}
];

test(function() {
  for (var i = 0; i < values.length; ++i) {
    assert_equals(values[i].input.ax, values[i].ax);
    assert_equals(values[i].input.ay, values[i].ay);
  }
}, "Test that the (ax, ay) values for CSSSkew are correct.");

test(function() {
  for (var i = 0; i < values.length; ++i) {
    assert_true(values[i].input.is2D());
  }
}, "Test that the is2D values for CSSSkew is correct.");

test(function() {
  for (var i = 0; i < values.length; ++i) {
    assert_equals(values[i].input.cssText, values[i].cssText);
  }
}, "Test that the cssText for CSSSkew is correct.");

test(function() {
  assert_throws(null, function() { new CSSSkew(); });
  assert_throws(null, function() { new CSSSkew(1); });
}, "Test that invalid number of arguments for CSSSkew throws an exception.");

function tanDegrees(degrees) {
  var radians = degrees * Math.PI / 180;
  return Math.tan(radians);
}

test(function() {
  for (var i = 0; i < values.length; ++i) {
    var input = values[i].input;
    var inputAsMatrix = input.asMatrix();
    assert_true(inputAsMatrix.is2D());
    var tanAx = tanDegrees(input.ax);
    var tanAy = tanDegrees(input.ay);
    var expectedMatrix = new CSSMatrixTransformComponent(1, tanAy, tanAx, 1, 0, 0);
    for (var attribute in expectedMatrix) {
      if (typeof expectedMatrix[attribute] === "number") {
        assert_approx_equals(inputAsMatrix[attribute], expectedMatrix[attribute], EPSILON);
      } else {
        assert_equals(inputAsMatrix[attribute], expectedMatrix[attribute]);
      }
    }
  }
}, "Test that asMatrix is constructed correctly for CSSSkew.");

</script>