With practically everything else in place, we finally turn to writing test specifications. Mocha BDD specifications are declared using the it() function with the following function signature:

it(description, callback);

The description string, by convention, is a statement of the expected behavior under test, and the callback function executes the tests. For example, assuming we have an empty this.notes collection variable, a test of the default values in App.Collections.Notes can be as simple as the following:

it("has default values", function () {
  expect(this.notes).to.be.ok;
  expect(this.notes).to.have.length(0);
});