If you're running a keyword test via script, especially in a data driven environment where the data dictates which test to execute, it would be useful to be able to get a count of the parameters on a...
OK... that JScript vs. JavaScript thing is really starting to bug me...
Your code works fine so long as the array AND the RunKeywordTests method are both JavaScript...
...but my Array is coming from a Script Extension which is a JScript array... which doesn't have all that fancy stuff available to me... and so, it doesn't work. So, I have to do some conversion work to turn my parameter list into an array that works with JavaScript.