Streaming Data with Ajax and Comet - Test-Driven JavaScript Development - page 327

assertNoException(function () {
this.client.dispatch();
}.bind(this));
},
"test should not throw if event is null": function () {
assertNoException(function () {
this.client.dispatch({ myEvent: null });
}.bind(this));
}
});
Running the tests somewhat surprisingly reveals that only the last test fails.
The tddjs.each method that is used for looping was built to handle input not
suitable for looping, so dispatch can already handle null and a missing data
argument. To pass the last test, we need to be a little more careful in the loop over
event objects, as seen in Listing 13.52.
Listing 13.52 Carefully looping event data
function dispatch(data) {
/* ... */
tddjs.each(data, function (topic, events) {
var length = events && events.length;
for(vari=0;i<length; i++) {
observers.notify(topic, events[i]);
}
});
}
In order to make the dispatch test case complete, we should add some tests
that make sure that notify is really called for all topics in data , and that all events
are passed to observers of a topic. I'll leave doing so as an exercise.
13.4.4 Adding Observers
With a functional dispatch we have what we need to test the observe method.
Listing 13.53 shows a simple test that expects that observers to be called when data
is available.