How to Jasmine Test JavaScript function with Parameter

Here is my code:

var action = function getParam(name){
   if(name=(new RegExp('[?&]'+encodeURIComponent(name)+'=([^&]*)')).exec(location.search))
      return decodeURIComponent(name[1]);
}
var code = action("code");

//This is the test framework that I got

it("should return the first param of location search", function() {
            var testCode = 
            //Here is where I want to call the function that tests my method. 
            expect(action("code")).toBe("testParam");
        });

I am new to JavaScript and Jasmine Testing. Thank you very much for your help.