React Native Quality Control & Assurance 4

Question 1

Which command runs only tests related to files changed since the last git commit in a Jest watch session?

Accepted Answer

jest --watch (press 'o')

Answer

In jest --watch mode, pressing 'o' runs only tests related to changed files, speeding up the feedback loop.

Question 2

What is the purpose of the `testID` prop in React Native components?

Accepted Answer

It provides a stable identifier for automated testing tools to locate elements

Answer

The testID prop maps to accessibilityIdentifier (iOS) and resource-id (Android), allowing test frameworks to reliably find elements.

Question 3

In React Native, which linting rule helps prevent accessibility issues that would fail QA audits?

Accepted Answer

eslint-plugin-jsx-a11y rules

Answer

eslint-plugin-jsx-a11y enforces accessibility best practices at the code level, catching issues before manual QA.

Question 4

When writing a React Native integration test that calls a real API, what is the best practice to avoid test instability?

Accepted Answer

Mock the network layer using msw or jest.mock on fetch/axios

Answer

Mocking the network layer with tools like msw (Mock Service Worker) or jest.mock keeps tests fast, deterministic, and offline-capable.

Question 5

What does the `--forceExit` flag do when added to a Jest command?

Accepted Answer

Terminates the Jest process after all tests complete even if async operations are still running

Answer

--forceExit ensures Jest exits after tests finish even if open handles (like setInterval or unclosed connections) would otherwise keep the process alive.

React Native Practice Test

React Native Practice Test

React Native Quality Control & Assurance 4