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Testing Generator Component Rendering in Create-React-App

This test suite validates the implementation of JavaScript generators in a React component within Create React App. It ensures proper rendering and async functionality of generator-based components through Jest unit testing.

Test Coverage Overview

The test coverage focuses on the basic rendering functionality of a React component that utilizes generators.

Tests asynchronous rendering behavior
Verifies component mounting without crashes
Validates Promise-based resolution
Covers generator component lifecycle

Implementation Analysis

The testing approach employs Jest’s asynchronous testing capabilities combined with React’s rendering lifecycle. It uses a Promise-based pattern to verify component mounting, demonstrating integration between React’s rendering and generator functions.

Utilizes Promise-based assertions
Implements ReactDOM.render with callback
Handles async component initialization

Technical Details

Jest test framework
React DOM testing utilities
Document createElement for test container
Promise-based async testing
Component callback pattern

Best Practices Demonstrated

The test suite exemplifies clean testing practices for async React components. It demonstrates proper test isolation through creating new DOM elements for each test, proper async handling with Promises, and clear test case organization.

Isolated test environment
Async test handling
Component cleanup
Clear test case structure

facebook/create-react-app

packages/react-scripts/fixtures/kitchensink/template/src/features/syntax/Generators.test.js

            
/**
 * Copyright (c) 2015-present, Facebook, Inc.
 *
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 */

import React from 'react';
import ReactDOM from 'react-dom';
import Generators from './Generators';

describe('generators', () => {
  it('renders without crashing', () => {
    const div = document.createElement('div');
    return new Promise(resolve => {
      ReactDOM.render(<Generators onReady={resolve} />, div);
    });
  });
});