webpack/TESTING_DOCS.md

# Webpack Test Suite Structure

This document explains the structure of the `test/` directory in the Webpack project using Jest. The directory is organized into multiple folders and files, each serving a specific purpose in testing various aspects of Webpack’s functionality.

## Folder and File Breakdown

### 1. `__snapshots__/`

- **Purpose**: Stores Jest snapshot files for comparing output consistency over time.
- **Usage**: Used for testing UI components, serialized data, or expected module outputs.

### 2. `benchmarkCases/`

- **Purpose**: Contains test cases for benchmarking Webpack's performance.
- **Usage**: Measures build times, memory usage, and optimization impact.

### 3. `cases/`

- **Purpose**: General test cases covering core functionalities.
- **Usage**: Includes unit and integration tests for various modules and features.

### 4. `configCases/`

- **Purpose**: Tests related to Webpack configurations.
- **Usage**: Ensures that Webpack’s configuration (e.g., loaders, plugins) functions correctly.

### 5. `fixtures/`

- **Purpose**: Stores sample/mock data used in tests.
- **Usage**: Helps in creating consistent test cases with predefined inputs.

### 6. `helpers/`

- **Purpose**: Utility functions and scripts to assist in testing.
- **Usage**: Provides reusable functions for mock data generation, cleanup, and assertions.

### 7. `hotCases/`

- **Purpose**: Focuses on Webpack’s Hot Module Replacement (HMR) functionality.
- **Usage**: Ensures live reloading and hot updates work correctly.

### 8. `hotPlayground/`

- **Purpose**: An experimental space for testing HMR features.
- **Usage**: Allows exploration of new HMR implementations.

### 9. `memoryLimitCases/json`

- **Purpose**: Contains test cases related to memory limits.
- **Usage**: Ensures Webpack doesn’t exceed memory constraints.

### 10. `statsCases/`

- **Purpose**: Tests focused on Webpack’s statistical outputs.
- **Usage**: Verifies correct bundle sizes, dependencies, and optimizations.

### 11. `typesCases/`

- **Purpose**: Type-checking tests, likely for TypeScript integration.
- **Usage**: Ensures proper type definitions and compliance.

### 12. `watchCases/`

- **Purpose**: Tests for Webpack’s watch mode functionality.
- **Usage**: Ensures file changes trigger correct rebuild behavior.

### 13. `*.unittest.js`

- **Purpose**: Contains unit tests for various functionalities.
- **Usage**: Ensures individual modules and functions work as expected.

### 14. `BannerPlugin.test.js`

- **Purpose**: Tests Webpack’s `BannerPlugin` functionality.
- **Usage**: Ensures that the plugin correctly adds banners to the bundled files.

## Testing Framework

- **Jest** is used for running tests.
- Snapshots help maintain consistency in output.
- Unit tests verify individual module functionality.
- Integration tests ensure multiple components work together.

## How to Run Tests

To execute all tests, use the following command:

```sh
yarn test
```

For running specific tests:

```sh
jest cases/userLogic.test.js
```

## Contribution Guide

- Add new test cases in the appropriate folder.
- Use Jest assertions and mocks for consistency.
- Run `yarn test` before pushing changes to validate functionality.