Sinon.JS stub for window.location.search

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.

score 6 · Accepted Answer · answered Aug 15 '12 at 15:20

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.

Chris Salzberg · Answer 2 · 2012-08-14T22:23:00.890

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")

edited Aug 14 '12 at 22:23

answered Aug 14 '12 at 20:50

Chris Salzberg

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I've tried that one before and I just tried it again: `TypeError: Attempted to wrap string property search as function` – Michael D Johnson Aug 14 '12 at 21:16
oh sorry, `window.location.search` is a string not a function, so you can't stub it. Replace the stub with an assignment: `window.location.search = "myUrl"`. – Chris Salzberg Aug 14 '12 at 21:24
Weird, performing a console.log before and after results in a blank string so I'm not sure what's going on. The assignment isn't sticking. I updated my code to show my test case as well. – Michael D Johnson Aug 14 '12 at 22:05
ok, I think this is actually harder than I originally thought. See this discussion: https://groups.google.com/forum/?fromgroups#!topic/sinonjs/MMYrwKIZNUU%5B1-25%5D – Chris Salzberg Aug 14 '12 at 22:21
This didn't work on my class since I had to use prototype to overide the function. Sinon's stub would not work with my class because of this. – Michael D Johnson Aug 15 '12 at 15:25

Sinon.JS stub for window.location.search

2 Answers2