Angular Web Framework Testing & Debugging 3

Question 1

What is the role of `HttpTestingController` in Angular testing?

Accepted Answer

It intercepts HTTP requests and allows asserting their parameters and flushing responses

Answer

HttpTestingController lets tests verify that specific HTTP requests were made and manually control the responses returned to the service under test.

Question 2

In Protractor or Cypress E2E tests for Angular, what does waiting for Angular's stability mean?

Accepted Answer

Waiting until all pending HTTP requests and asynchronous tasks in Angular's zone have completed

Answer

Angular stability means Zone.js has no pending microtasks or macrotasks, ensuring the DOM is in a settled state before assertions run.

Question 3

Which Jasmine function is used to set up shared initialization code that runs before each test in a describe block?

Accepted Answer

beforeEach()

Answer

beforeEach() runs its callback before every it() block in its enclosing describe, making it ideal for resetting state between tests.

Question 4

What does calling `fixture.nativeElement.querySelector('.my-class')` return in a component test?

Accepted Answer

The DOM element matching the CSS selector within the component's rendered template

Answer

fixture.nativeElement is the real DOM element of the component's host, so querySelector returns the matching native DOM node.

Question 5

In Angular testing, what is the difference between `DebugElement.query()` and `DebugElement.queryAll()`?

Accepted Answer

query() returns the first matching DebugElement; queryAll() returns an array of all matches

Answer

query() finds the first DebugElement matching a predicate (like By.css()), while queryAll() returns every matching DebugElement in the subtree.

Angular Web Framework Practice Test