Test-Driving JavaScript Applications

Test-Drive the Service

The service class needs to provide a get function. This function will talk to the back end, fetch the data, extract the JSON response, and return an Observable to the caller. Let’s design this function, test first.

As the first step, let’s list the tests we need to implement the get function. Here again you can learn from the service you created during the spiking exercise.

• get should make GET request to /tasks
• extractData should return result from json()
• extractData should throw exception for invalid status
• returnError should return the error Observable

The first test is going to be an interaction test. The methods of HTTP return Rx.Observable. We will be calling the map and catch functions on the returned Observable ...