Testing routers in backbone.js properly?

Question

So I\'ve just started to write tests for my in-progress javascript app, using sinon.js & jasmine.js. Works pretty well overall, but I need to also

Answer 1

I started out using ggozad's solution of spying on _updateHash which partially worked for me. However, I discovered that my tests were confused because the hash never updated, so code that relied upon calls to getHash or getFragment were failing.

What I ended up with is the following helper function that spies on both _updateHash and getHash. The former records the request to update the hash, and the latter returns the last hash that was passed to _updateHash. I call this helper function in my tests before I start the Backbone history.

    /**
     * Prevent Backbone tests from changing the browser's URL.
     *
     * This function modifies Backbone so that tests can navigate
     * without modifying the browser's URL. It works be adding
     * stub versions of Backbone's hash functions so that updating
     * the hash doesn't change the URL but instead updates a
     * local object. The router's callbacks are still invoked
     * so that to the test it appears that navigation is behaving
     * as expected.
     *
     * Note: it is important that tests don't update the browser's
     * URL because subsequent tests could find themselves in an
     * unexpected navigation state.
     */
    preventBackboneChangingUrl = function() {
        var history = {
            currentFragment: ''
        };

        // Stub out the Backbone router so that the browser doesn't actually navigate
        spyOn(Backbone.history, '_updateHash').andCallFake(function (location, fragment, replace) {
            history.currentFragment = fragment;
        });

        // Stub out getHash so that Backbone thinks that the browser has navigated
        spyOn(Backbone.history, 'getHash').andCallFake(function () {
            return history.currentFragment;
        });
    };