Recently I had to write some fairly substantial javascript, and in the process I was reminded of how fast javascript, like most scripting languages, and get out of hand really quick. I took a step back and thought why should I work in javascript any different then I do in other language? Just because it’s a scripting language doesn't make it any less valid of a development platform, and I can apply the same design pattern and principles I would with anything else.
So The first thing I did was went looking for a unit testing framework and I found JSUnit. JSUnit is available from http://www.jsunit.net/ and is a port of the JUnit framework to javascript. The entire testing framework and test runner is written in javascript so I can use it anywhere you use javascript and in any development platform(php, ruby, Perl, java, .net, etc).
Getting started I have this javascript function I want to test
1: function addTwoNumber(x, y) {
2: var result = x + y;
3: return result;
4: }so first I create an html page and add the jsUnitCore.js and my .js file containing this function (almost all of your javascript really should be in .js files for a number of reasons, but that’s another blog post).
1: <html> 2: <head> 3: <script language="JavaScript" src="jsUnitCore.js"></script>
4: <script language="JavaScript" src="javascriptCode.js"></script>
5: </head> 6: <body> 7: </body> 8: </html>then to add test cases I create functions inside a script tag in the body of the html page like so
1: <body> 2: <script type="text/javascript">
3: function test_addTwoNumber_TwoNumbersAreAdded() {
4: var result = addTwoNumber(2, 2);
5: assertEquals("Adds 2 values together", 4, result);
6: } 7: 8: </script> 9: </body>
then add the file location and run the tests, it’s that simple. If you look at the screen shot you will notice that I’m using opera, for what ever reason I couldn’t get the test runner to work in Firefox, every time I would try and run my test file I would get a time out error, The funny thing is it works in IE, Chrome, and Opera just fine, weird.
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