FireUnit makes it quick and easy to write unit tests in JavaScript, doing something like the following:

fireunit.ok(foo==bar, 'foo should equal bar');

But what if you need to do something a little more complex than a one liner? You can write and execute an anonymous function, like this:

fireunit.ok(function(){
    var myList = $('ul');
    var originalLen = myList.children('li').length;
    fireunit.click( myList );
    return $(myList).children() == originalLen + 1;
}(), 'This test should return true');

Two things to note here:

1. Make sure that you include the extra parentheses after the function definition; this executes the function straight away
2. Make sure you  return true or false  from the function (or an expression that evaluates to true or false.)