webpack-integration.test.js

import fs from 'fs'
import path from 'path'
import webpack from 'webpack'
import ExtractPlugin from 'extract-text-webpack-plugin'

const cases = process.env.CASES
  ? process.env.CASES.split(',')
  : fs.readdirSync(path.join(__dirname, 'cases'))

describe('Webpack Integration Tests', () => {
  cases.forEach(testCase => {
    it(testCase, done => {
      let options = { entry: { test: './index.js' } }
      const testDirectory = path.join(__dirname, 'cases', testCase)
      const outputDirectory = path.join(__dirname, 'js', testCase)
      const configFile = path.join(testDirectory, 'webpack.config.js')

      if (fs.existsSync(configFile)) {
        options = require(configFile)
      }
      options.context = testDirectory
      if (!options.module) options.module = {}
      if (!options.module.loaders) {
        options.module.loaders = [
          { test: /\.txt$/, loader: ExtractPlugin.extract('raw-loader') }
        ]
      }
      if (!options.output) options.output = { filename: '[name].js' }
      if (!options.output.path) options.output.path = outputDirectory
      if (process.env.CASES) {
        console.log(
          `\nwebpack.${testCase}.config.js ${JSON.stringify(options, null, 2)}`
        )
      }

      webpack(options, (err, stats) => {
        if (err) return done(err)
        if (stats.hasErrors()) return done(new Error(stats.toString()))
        const testFile = path.join(outputDirectory, 'test.js')
        if (fs.existsSync(testFile)) {
          require(testFile)(suite)
        }
        const expectedDirectory = path.join(testDirectory, 'expected')
        fs.readdirSync(expectedDirectory).forEach(file => {
          const filePath = path.join(expectedDirectory, file)
          const actualPath = path.join(outputDirectory, file)
          expect(readFileOrEmpty(actualPath)).toEqual(readFileOrEmpty(filePath))
          expect(readFileOrEmpty(actualPath)).toMatchSnapshot()
        })
        done()
      })
    })
  })
})

function readFileOrEmpty(path) {
  try {
    return fs.readFileSync(path, 'utf-8')
  } catch (e) {
    return ''
  }
}