Testing Reusable Components

1. Introduction

Testing reusable components is an essential aspect of Component-Driven Development (CDD). This lesson will guide you through the fundamental principles of testing reusable components, including key concepts, methodologies, and best practices.

2. Key Concepts

3. Testing Strategies

There are several strategies for testing reusable components:

• Unit Testing: Testing individual components in isolation.
• Integration Testing: Testing how components interact with each other.
• End-to-End Testing: Testing the entire application flow including the components.

3.1 Unit Testing Example

Here’s a simple example of a unit test for a reusable button component using Jest:

import { render, screen } from '@testing-library/react';
import Button from './Button';

test('renders button with correct text', () => {
    render();
    const buttonElement = screen.getByText(/click me/i);
    expect(buttonElement).toBeInTheDocument();
});

4. Best Practices

• Write tests for all critical paths in your components.
• Use descriptive names for your test cases.
• Keep your tests isolated and independent.
• Utilize mocking to isolate components from external dependencies.

5. FAQ

Flowchart: Testing Workflow

graph TD;
            A[Start] --> B{Is the component reusable?}
            B -- Yes --> C[Write Unit Tests]
            B -- No --> D[Refactor Component]
            C --> E[Run Tests]
            E --> F{All tests pass?}
            F -- Yes --> G[Component Ready]
            F -- No --> H[Debug Tests]
            H --> E
            D --> B
            G --> I[End]