When using Jasmine for unit testing in Angular, what function is used to create a group of related tests?
- afterEach()
- beforeAll()
- describe()
- it()
In Jasmine, the describe() function is used to create a group of related tests, which helps organize and structure your test suite.
In Angular, when using a hot observable, what happens to the data emissions when there are no subscribers?
- Data emissions are buffered and sent to the next subscriber when they subscribe.
- Data emissions are cached and sent to the first subscriber who subscribes.
- Data emissions are lost if there are no subscribers.
- Data emissions are sent to a separate storage location for later retrieval.
When using a hot observable in Angular, data emissions are lost if there are no subscribers. They are not cached or buffered for future subscribers.
You are writing a test for an Angular component that renders a list of items. You want to test that when a new item is added, it is correctly displayed in the component. Which testing technique or utility would be best suited for this?
- End-to-End Testing with Protractor
- Integration Testing with Karma and Jasmine
- No testing needed - it's an Angular feature
- Unit Testing with TestBed
For testing component behavior in isolation, Unit Testing with TestBed is the most suitable approach. It allows you to create an isolated testing environment for the component.
What is the role of fixture in Angular component tests?
- Hold data
- Manage test configuration
- Render the component
- Simulate user interactions
The role of the fixture in Angular component tests is to render the component for testing and provide a handle for simulating user interactions.
How can you test that a directive correctly responds to changes in input values?
- Directly manipulate the directive's DOM elements and observe changes
- Manually update the directive's input values and check the DOM
- Use the TestBed's detectChanges method to trigger change detection
- Use the ng test CLI command to automate the testing process
To test that a directive correctly responds to input value changes, you should use the TestBed's detectChanges method to trigger change detection.
The _____ method in a Route Guard is used to check whether a user can navigate to a specific route.
- canActivate
- canDeactivate
- canNavigateTo
- checkRouteAccess
The canActivate method in a Route Guard is used to check whether a user can navigate to a specific route by returning true or false based on certain conditions.
What is the primary purpose of Dependency Injection (DI) in Angular?
- Define component behavior
- Enable two-way data binding
- Handle HTTP requests
- Manage external dependencies
The primary purpose of Dependency Injection (DI) in Angular is to manage external dependencies by providing them to a component when it's created.
What are the implications of importing a module that provides a service into multiple feature modules?
- Compilation error
- Multiple service instances
- No implications
- Shared singleton service instance
Importing a module with a service into multiple feature modules results in a shared singleton service instance, allowing data to be shared.
How does Angular Universal improve the perceived performance of an application?
- It enhances routing performance
- It improves code quality
- It reduces the bundle size
- It speeds up the initial rendering of a page
Angular Universal improves the perceived performance of an application by speeding up the initial rendering of a page on the server side.
In an Angular application, you want to ensure that data for a specific route is fetched and ready before the route is activated. How would you achieve this?
- Configure route preloading strategies to ensure data is available before route activation.
- Fetch data in the route component's constructor and use a loading spinner until it's available.
- Implement a global data service to fetch data, and check data availability in the route's lifecycle hooks.
- Use route resolvers to fetch and resolve the data before activating the route.
To ensure that data for a specific route is fetched and ready before the route is activated, you should use route resolvers. Resolvers fetch and resolve the data before activating the route, ensuring the data is available when the route component is initialized.