<html>
<head>
<meta charset='utf-8'>
<style>
.pass {
    font-weight: bold;
    color: green;
}
.fail {
    font-weight: bold;
    color: red;
}
</style>

<script>
if (window.testRunner)
    testRunner.dumpAsText();

function SputnikError(message)
{
    this.message = message;
}

SputnikError.prototype.toString = function ()
{
    return 'SputnikError: ' + this.message;
};

var sputnikException;

function testPrint(msg)
{
    var span = document.createElement("span");
    document.getElementById("console").appendChild(span); // insert it first so XHTML knows the namespace 
    span.innerHTML = msg + '<br />';
}

function escapeHTML(text)
{
    return text.toString().replace(/&/g, "&amp;").replace(/</g, "&lt;");
}

function printTestPassed(msg)
{
    testPrint('<span><span class="pass">PASS</span> ' + escapeHTML(msg) + '</span>');
}

function printTestFailed(msg)
{
    testPrint('<span><span class="fail">FAIL</span> ' + escapeHTML(msg) + '</span>');
}

function testFailed(msg)
{
    throw new SputnikError(msg);
}

var successfullyParsed = false;
</script>

</head>
<body>
<p>S15.8.2.7_A6</p>
<div id='console'></div>
<script>
try {

/**
 * @name: S15.8.2.7_A6;
 * @section: 15.8.2.7;
 * @assertion: Cosine is a periodic function with period 2*PI;
 * @description: Checking if Math.cos(x) equals to Math.cos(x+n*2*Math.PI) with precision 0.000000000003, where n is an integer from 1 to 100 and x is one of 10 float point values from -Math.PI to +Math.PI; 
 */
 
// CHECK#1
  prec = 0.000000000003;
//prec = 0.000000000000001;
period = 2*Math.PI;
pernum = 100;

a = -pernum * period;
b = pernum * period;
snum = 9; 
step = period/snum + 0.0;
x = new Array();
for (i = 0; i < snum; i++)
{
	x[i] = a + i*step;
}
x[9] = a + period;

var curval;
var curx;
var j;
for (i = 0; i < snum; i++)
{
	curval = Math.cos(x[i]);
	curx = x[i] + period;
	j = 0;
	while (curx <= b)
	{
		curx += period;
		j++;
		if (Math.abs(Math.cos(curx) - curval) >= prec)
		{
			testFailed("#1: cos is found out to not be periodic:\n Math.abs(Math.cos(" + x[i] + ") - Math.cos(" + x[i] + " + 2*Math.PI*" + j + ")) >= " + prec + "\n Math.cos(" + x[i] + ") === " + curval + "\n Math.cos(" + curx + ") === " + Math.cos(curx));
		}
	}
}

} catch (ex) {
    sputnikException = ex;
}

var successfullyParsed = true;
</script>

<script>
if (!successfullyParsed)
    printTestFailed('successfullyParsed is not set');
else if (sputnikException)
    printTestFailed(sputnikException);
else
    printTestPassed("");
testPrint('<br /><span class="pass">TEST COMPLETE</span>');
</script>
</body>
</html>