Learning jQuery - Fourth Edition

Adding and running tests

In test-driven development, we write tests before writing code. This way, we can observe when a test fails, add new code, and then see that the test passes, verifying that our change has the intended effect.

Let's start by testing the child selector that we used in Chapter 2, Selecting Elements, to add a horizontal class to all <li> elements that are children of <ul id="selected-plays">:

test('Child Selector', function() {
  expect(1);
  var topLis = $('#selected-plays > li.horizontal');
  equal(topLis.length, 3, 'Top LIs have horizontal class');
});

Listing B.2

Here we've actually introduced two tests. We begin with the expect() test, which tells QUnit how many tests we expect to run in this set. Then, because we're testing ...