Sinon.JS stub for window.location.search - coffeescript

Question

I am trying to test a simple function that makes a call to window.location.search. I'm trying to understand how to stub this call so that I can return a url of my choosing.
function:
getParameterByName: (name) =>
name = name.replace(/[\[]/, "\\\[").replace(/[\]]/, "\\\]")
regexS = "[\\?&]" + name + "=([^&#]*)"
regex = new RegExp(regexS)
results = regex.exec(window.location.search) //Stub call to window.location.search
if(results == null)
return ""
else
return decodeURIComponent(results[1].replace(/\+/g, " "))
Test case:
describe "Data tests", () ->
it "Should parse parameter from url", () ->
data = new Data()
console.log("search string: " + window.location.search) //prints "search string:"
window.location.search = "myUrl"
console.log("search string: " + window.location.search) //prints "search string:"
console.log(data.getParameterByName('varName'))
expect(true).toBe(true)
My original attempt was to return a value directly like so:
sinon.stub(window.location.search).returns("myUrl")
This, of course, doesn't work. I don't think I'm specifying the stub correctly, but it shows my intent.
Any ideas on how to solve this would be greatly appreciated.

Answer 1

So, as mentioned before, you can't mock window.location directly. Nor did the mylib.search wrapper idea work with my situation. So, what I did was break out my call to window.location.search into its own function. My new class looks like so:
getParameterByName: (name) =>
console.log("name: #{name}")
name = name.replace(/[\[]/, "\\\[").replace(/[\]]/, "\\\]")
regexS = "[\\?&]" + name + "=([^&#]*)"
regex = new RegExp(regexS)
results = regex.exec(#getWindowLocationSearch())
if(results == null)
return ""
else
return decodeURIComponent(results[1].replace(/\+/g, " "))
getWindowLocationSearch:() =>
window.location.search
Then in my test case, I replace the function with my test code like so:
describe "Data tests", () ->
it "Should parse parameter from localhost url", () ->
goodUrl = "http://localhost:3333/?token=val1"
Data::getWindowLocationSearch = () -> return goodUrl
unit = new Data()
result = unit.getParameterByName("token")
expect(result).toBe("val1")
For those who don't read Coffeescript, the equivalent javascript code is listed below:
it("Should parse parameter from localhost url", function() {
var goodUrl, result, unit;
goodUrl = "http://localhost:3333/?token=val1";
Data.prototype.getWindowLocationSearch = function() {
return goodUrl;
};
unit = new Data();
result = unit.getParameterByName("token");
expect(result).toBe("val1");
return expect(true).toBe(true);
});
As is my usual experience with Javascript. The working solution was not nearly as painful as the journey to get there. Thank you very much for your comments and contributions.

Answer 2

UPDATE: window.location, it seems, is a bit of a special case, see this discussion: https://groups.google.com/forum/?fromgroups#!topic/sinonjs/MMYrwKIZNUU%5B1-25%5D
The easiest way to solve this problem is to write a wrapper function around window.location, and stub that:
mylib.search = function (url) {
window.location.search = url;
};
And in your test:
sinon.stub(mylib, 'search').returns("myUrl")
ORIGINAL ANSWER:
Try this:
sinon.stub(window.location, 'search').returns("myUrl")