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Testing Component Tree Shaking Implementation in dcloudio/uni-app

This test suite evaluates tree shaking functionality in uni-app components for both Android and iOS builds. It verifies the proper component optimization and manifest generation across different build configurations, ensuring efficient bundle size management.

Test Coverage Overview

The test suite provides comprehensive coverage of component tree shaking across different platform builds.

Tests both Android and iOS build configurations
Validates manifest.json generation and content
Verifies proper environment variable handling
Ensures correct build output directory structure

Implementation Analysis

The testing approach utilizes Jest’s asynchronous testing capabilities to execute build scripts and verify outputs. It implements dynamic test generation based on build types and platforms, using fs-extra for file system operations and execa for process execution.

Dynamic test generation per platform/build type
Async/await pattern for build process handling
Environment variable injection for build configuration

Technical Details

Jest test framework with extended timeout (50s)
fs-extra for enhanced file system operations
execa for process execution and npm script running
Snapshot testing for manifest validation
Dynamic environment variable configuration

Best Practices Demonstrated

The test implementation showcases several testing best practices for build process validation.

Clean test environment setup with directory cleaning
Modular test configuration using object literals
Snapshot testing for consistent manifest validation
Proper error handling and process management
Clear test case isolation and setup

dcloudio/uni-app

packages/playground/__tests__/app-components-tree-shaking.spec.ts

            
import fs from 'fs-extra'
import path from 'path'
import execa from 'execa'

const projectDir = path.resolve(__dirname, '../app-components-tree-shaking')

describe('app-components-tree-shaking playground', () => {
  jest.setTimeout(50 * 1000)
  const types = {
    'uni-app-x': ['build:app-android', 'build:app-ios'],
  }
  const distDir = path.resolve(projectDir, 'dist')
  if (fs.existsSync(distDir)) {
    fs.emptyDirSync(distDir)
  }
  Object.keys(types).forEach((type) => {
    const scripts = types[type]
    scripts.forEach((script) => {
      const mode = script.split(':')[0]
      const platform = script.split(':')[1]
      test(`${type} ${script}`, async () => {
        const outDir = path.resolve(distDir, mode, type, platform)
        console.log(`${type} npm run ${script} start`)
        await execa('npm', ['run', script], {
          cwd: projectDir,
          env: {
            ...process.env,
            UNI_OUTPUT_DIR: outDir,
            UNI_APP_X: type === 'uni-app-x' ? 'true' : 'false',
          },
        })
        console.log(`${type} npm run ${script} end`)
        const manifest = JSON.parse(
          fs.readFileSync(path.resolve(outDir, 'manifest.json'), 'utf-8')
        )
        // 里边的版本号会变更，移除影响
        delete manifest['uni-app-x']
        expect(JSON.stringify(manifest, null, 2)).toMatchSnapshot()
      })
    })
  })
})