Question

I’m just getting started with Knockout JS and with QUnit for doing unit tests of my knockout view model. The problem that I’m running into is that if I have multiple tests in my qunit test javascript file, and I link to a javascript file which includes my View Model definition… any changes that I make to the View Model in one test are also present when I start the next test in the test module. I’m used to have an NUnit environment where my state is cleared automatically between tests.

Is there a method, pattern or example that someone can point to which shows the best way to define a view model, and have it reset it’s state for the start of each unit test?

Answer 1

Are you using the second parameter (lifecycle) of module? If not, you should be able to instantiate your view model at this level, something like:

module("foo", {
    setup: function() {
        this.model = instantiateModel();
    },
    tearDown: function() {
        // execute reset here
    });

test("bar", function() {
    ok(this.model.hasSomething() !== null, "msg");
});

From what I remember reading, QUnit tets are run in the same scope as setup and tearDown, so any members defined in setup will be accessible within any subsequent tests.