Component testing in React Native - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is component testing in React Native?

Component testing checks if a single UI component works correctly by itself, without involving the whole app.

intermediate

Why do we use shallow rendering in component testing?

Shallow rendering tests a component without rendering its child components, making tests faster and focused.

beginner

Which library is commonly used for React Native component testing?

React Native Testing Library is popular because it encourages testing components like users interact with them.

intermediate

What does a snapshot test do in component testing?

A snapshot test saves the rendered output of a component and compares it later to detect unexpected changes.

intermediate

How can you simulate a button press in React Native component tests?

You can simulate a button press by firing a press event using fireEvent.press from React Native Testing Library.

What is the main goal of component testing in React Native?

A Test backend API responses

B Test the entire app navigation

C Test device hardware features

D Test a single UI component in isolation

Component testing focuses on checking one UI component alone to ensure it works as expected.

Which method helps to avoid rendering child components during tests?

A Shallow rendering

B Full rendering

C Snapshot testing

D Integration testing

Shallow rendering renders only the component itself, not its children, making tests simpler.

Which library is best suited for user-focused React Native component testing?

A Mocha

B Jest DOM

C React Native Testing Library

D Enzyme

React Native Testing Library encourages testing components as users interact with them.

What does a snapshot test compare?

A Rendered output over time

B Component code style

C API response times

D Device compatibility

Snapshot tests compare the saved rendered output to the current output to catch changes.

How do you simulate a button press in React Native Testing Library?

A triggerEvent(buttonElement, 'click')

B fireEvent.press(buttonElement)

C simulatePress(buttonElement)

D buttonElement.click()

fireEvent.press simulates a press event on a button in React Native Testing Library.

Explain the purpose and benefits of component testing in React Native.

Think about testing one piece of the UI alone before the whole app.

Describe how you would write a simple test to check if a button press calls a function in React Native.

Use React Native Testing Library and fireEvent.press.