Types of React js test cases

In React.js, testing involves different types of test cases based on the scope and type of component or functionality being tested. Here’s a breakdown of the common types:

1. Unit Tests

• Purpose: Verify that individual units (usually functions, components, or classes) work as expected.
• Examples:
  • Testing if a function returns the correct output.
  • Checking if a component renders correctly with given props.
• Tools: Jest, React Testing Library, Enzyme

2. Component Tests

• Purpose: Test individual components in isolation to ensure they behave as expected given different props, states, or events.
• Examples:
  • Testing if a component displays correctly with a certain prop.
  • Checking if a component renders specific elements based on state or prop values.
• Tools: React Testing Library, Enzyme

3. Integration Tests

• Purpose: Test how multiple units (components, hooks, or modules) work together.
• Examples:
  • Testing how a parent component renders multiple child components.
  • Ensuring a component updates state and re-renders correctly when an event is triggered.
• Tools: React Testing Library, Jest

4. End-to-End (E2E) Tests

• Purpose: Test the full application flow from a user’s perspective. E2E tests simulate actual user interactions to ensure the entire app works as expected.
• Examples:
  • Verifying that a user can fill out a form, submit it, and see a success message.
  • Testing if a user can navigate between pages or access different features.
• Tools: Cypress, Playwright, Selenium

5. Snapshot Tests

• Purpose: Capture a snapshot of a component’s output (rendered DOM) and compare it with a baseline snapshot to detect unintended changes.
• Examples:
  • Capturing a snapshot of a header component and ensuring it hasn’t changed unexpectedly.
• Tools: Jest

6. Performance Tests

• Purpose: Measure and test the performance of components and ensure they don’t degrade the app’s efficiency.
• Examples:
  • Ensuring components load within an acceptable time.
  • Measuring render times or component load times.
• Tools: React Profiler, Lighthouse

7. Accessibility Tests

• Purpose: Verify that the components comply with accessibility standards, ensuring they’re usable by people with disabilities.
• Examples:
  • Checking if images have alt tags.
  • Ensuring interactive elements are keyboard-navigable.
• Tools: axe-core, jest-axe, React Testing Library

8. Behavioral Tests

• Purpose: Test expected behaviors in a component, particularly with complex logic.
• Examples:
  • Ensuring form submission behaves as expected under different conditions.
  • Checking if a modal closes when clicking outside it.
• Tools: React Testing Library, Enzyme, Jest

9. Hook Tests

• Purpose: Test custom hooks or built-in hooks used within components.
• Examples:
  • Testing a custom hook that fetches data.
  • Ensuring useState updates correctly when an action is triggered.
• Tools: React Testing Library