Besides its HTML fixture module, the Jasmine jQuery extension comes with a set of custom matchers, which help in writing expectations with elements in the DOM.

The biggest advantage of using these custom matchers, as demonstrated, is the better error messages they generate. So although you can write all your specs without using any of these matchers, doing so would get you much more useful information when an error happens.

To better understand this advantage, we can revisit the example of the spec should expose a property with its DOM element. There, it uses the toExist matcher:

it("should expose a property with its DOM element", function() {
  expect(view.$el).toExist();
});

If this spec fails, we get a nice error message:

Nice custom matcher error message

But if we rewrite this spec without the custom matcher (still making the same validation):

it("should expose a property with its DOM element", function() {
  expect($(document).find(view.$el).length).toBeGreaterThan(0);
});

The error message gets less informative:

By reading the error you can't understand what it is truly testing

So use these matchers whenever you can to get better error messages. Let's go over some of the available custom matchers, demonstrated by example, with these acceptance criteria of the NewInvestmentView class:

It is important that you understand that these next examples, although useful to demonstrate how the Jasmine jQuery matchers work, are not really testing any JavaScript code, but only the HTML elements that were loaded by the HTML Fixture.

it("should allow the input of the stock symbol", function() {
  expect(view.$el.find('.new-investment-stock-symbol')).toBe('input[type=text]'),
});

it("should allow the input of shares", function() {
  expect(view.$el).toContainHtml('<input type="number" class="new-investment-shares" name="shares" value="0">'),
});

it("should allow the input of the share price", function() {
  expect(view.$el).toContain('input[type=number].new-investment-share-price'),
});

it("should have an empty stock symbol", function() {
  expect(view.$el.find('.new-investment-stock-symbol')).toHaveValue(''),
});

it("should have its shares value to zero", function() {
  expect(view.$el.find('.new-investment-shares')).toHaveValue('0'),
});

it("should have its share price value to zero", function() {
  expect(view.$el.find('.new-investment-share-price')).toHaveAttr('value', '0'),
});

it("should have its stock symbol input on focus", function() {
  expect(view.$el.find('.new-investment-stock-symbol')).toBeFocused();
});

it("should not allow to add", function() {
  expect(view.$el.find('input[type=submit]')).toBeDisabled();
});