include ../../../../_includes/_util-fns :marked We’ll need an Angular application to test, one as simple as possible while having all the angular features we want to test. It’s a one-screen variation on the “Tour of Heroes” that should be familiar to you as a reader of this Developers Guide. Our test app displays a list of heroes - all favorites of the user named “Bongo”. It looks like this: figure.image-display img(src='/resources/images/devguide/application-under-test/bongos-heroes.png' style="width:400px;" alt="Bongo's Heroes") :marked At the top is a master list of heroes; at the bottom the detail for the current hero. Click a hero in the list to change the current hero. Change the name in the textbox and that name updates everywhere. The *Update* button modifies the `Hero.name` in an arbitrary way and that change also propagates everywhere on screen. The *Delete* button deletes the hero from the list and a new hero becomes current. *Refresh* clears both the list and detail, then restores the original list of heroes. This simple app illustrates a number of Angular features that we’d like to test. - A simple service that presents the `username` (“Bongo”) - A dataservice that fetches and caches the list of heroes. - The dataservice depends in turn on another “backend” service that handles the interaction with a remote web api - A master `HeroesComponent` presents the list - The master communicates with a detail component `HeroDetailComponent` about the current hero both through an attribute and an event. - The detail’s template is nested within the master component’s template. - The `name` textbox illustrates two-way databinding - The update button demonstrates that a programmatic change to the databound model propagates to both component views - The delete button triggers an event that is caught by the parent component We’ll examine the implementation details as we evolve our tests. .l-main-section :marked ## What’s Next? Now that we’re familiar with how the test app works, we’re ready to poke at it with our [first application tests](first-app-tests.html) written in Jasmine.