React Native Quality Control & Assurance 5

Question 1

Which tool provides a dashboard for tracking React Native crash rates, ANRs, and performance in production?

Accepted Answer

Firebase Crashlytics

Answer

Firebase Crashlytics collects and reports production crashes, ANRs, and error trends with real-time dashboards.

Question 2

What does `expect(component).toMatchSnapshot()` do when run for the first time in a Jest test?

Accepted Answer

It creates a new snapshot file and passes the test

Answer

On first run, Jest creates a new .snap file with the serialized component output and the test passes; subsequent runs compare against it.

Question 3

In a React Native CI pipeline, what is the correct order for quality gates?

Accepted Answer

Lint → type check → unit tests → E2E tests

Answer

Running lint and type checks first catches cheap errors early; unit tests run next, and expensive E2E tests run last to minimize CI time.

Question 4

Which property in `jest.config.js` specifies which files to transform with Babel before running tests?

Accepted Answer

transform

Answer

The transform property maps file patterns to transformer packages (like babel-jest) so Jest can process JSX and modern JS syntax.

Question 5

What is the role of `@testing-library/jest-native` in React Native testing?

Accepted Answer

It extends Jest with custom matchers like toBeVisible() and toHaveTextContent()

Answer

@testing-library/jest-native adds semantic Jest matchers tailored to React Native elements, making assertions more expressive and readable.

React Native Practice Test