Adds tests for default webpack package config

Adds a root module to the npm pacakge to make it possible to customize
the RAILS_ROOT location. Supporting this approach means ensuring that
relative paths for various Webpack configuration items resolve relative
to the given root if it exists.

package.json

@@ -57,7 +57,7 @@
     "coffeescript": ">= 1.12.7 || >= 2.x"
   },
   "scripts": {
-    "test": "jest",
+    "test": "RAILS_ROOT=test/test_app jest",
     "lint": "eslint {package,lib}/"
   },
   "repository": {

package/__tests__/environment.js

@@ -0,0 +1,66 @@
+const { resolve, join } = require('path')
+const { sync } = require('glob')
+const assert = require('assert')
+
+const { ConfigList, ConfigObject } = require('../config_types')
+
+const Environment = require('../environment')
+
+describe('Environment', () => {
+  let environment;
+
+  describe('toWebpackConfig', () => {
+    beforeEach(() => {
+      environment = new Environment()
+    })
+
+    test('should return entry', () => {
+      const config = environment.toWebpackConfig()
+      expect(config.entry.application).toEqual(resolve('test', 'test_app', 'app', 'javascript', 'packs', 'application.js'))
+    })
+
+    test('should return output', () => {
+      const config = environment.toWebpackConfig()
+      expect(config.output.filename).toEqual('[name]-[chunkhash].js')
+      expect(config.output.chunkFilename).toEqual('[name]-[chunkhash].chunk.js')
+      expect(config.output.path).toEqual(resolve('test', 'test_app', 'public', 'packs-test'))
+      expect(config.output.publicPath).toEqual('/packs-test/')
+    })
+
+    test('should return default loader rules for each file in config/loaders', () => {
+      const config = environment.toWebpackConfig()
+      const rules = Object.keys(require('../rules'))
+      const [{ oneOf: configRules }] = config.module.rules;
+
+      expect(rules.length).toBeGreaterThan(1)
+      expect(configRules.length).toEqual(rules.length)
+    })
+
+    test('should return default plugins', () => {
+      const config = environment.toWebpackConfig()
+      expect(config.plugins.length).toEqual(4)
+    })
+
+    test('should return default resolveLoader', () => {
+      const config = environment.toWebpackConfig()
+      expect(config.resolveLoader.modules).toEqual([join('test', 'test_app','node_modules')])
+    })
+
+    test('should return default resolve.modules with additions', () => {
+      const config = environment.toWebpackConfig()
+      expect(config.resolve.modules).toEqual([
+        resolve('test', 'test_app', 'app', 'javascript'),
+        join('test', 'test_app', 'node_modules'),
+        resolve('test', 'test_app', 'app', 'assets'),
+        '/etc/yarn',
+      ])
+    })
+
+    test('returns plugins property as Array', () => {
+      const config = environment.toWebpackConfig()
+
+      expect(config.plugins).toBeInstanceOf(Array)
+      expect(config.plugins).not.toBeInstanceOf(ConfigList)
+    })
+  })
+})

package/asset_host.js

@@ -1,5 +1,5 @@
 const config = require('./config')
-const { resolve } = require('path')
+const { resolveRoot } = require('./root')
 
 const removeOuterSlashes = string =>
   string.replace(/^\/*/, '').replace(/\/*$/, '')
@@ -14,7 +14,7 @@ const formatPublicPath = (host = '', path = '') => {
 }
 
 module.exports = {
-  path: resolve('public', config.public_output_path),
+  path: resolveRoot('public', config.public_output_path),
   publicPath: `/${config.public_output_path}/`.replace(/([^:]\/)\/+/g, '$1'),
   publicPathWithHost: formatPublicPath(process.env.WEBPACKER_ASSET_HOST, config.public_output_path)
 }

package/config.js

@@ -1,10 +1,10 @@
-const { resolve } = require('path')
 const { safeLoad } = require('js-yaml')
 const { readFileSync } = require('fs')
 const deepMerge = require('./utils/deep_merge')
 
+const { resolveRoot } = require('./root')
 const defaultFilePath = require.resolve('../lib/install/config/webpacker.yml')
-const filePath = resolve('config', 'webpacker.yml')
+const filePath = resolveRoot('config', 'webpacker.yml')
 
 const environment = process.env.NODE_ENV || 'development'
 const defaultConfig = safeLoad(readFileSync(defaultFilePath), 'utf8')[environment]

package/environment.js

@@ -16,6 +16,7 @@ const { ConfigList, ConfigObject } = require('./config_types')
 const rules = require('./rules')
 const config = require('./config')
 const assetHost = require('./asset_host')
+const { root, resolveRoot } = require('./root')
 
 const getLoaderList = () => {
   const result = new ConfigList()
@@ -43,7 +44,7 @@ const getExtensionsGlob = () => {
 const getEntryObject = () => {
   const result = new ConfigObject()
   const glob = getExtensionsGlob()
-  const rootPath = join(config.source_path, config.source_entry_path)
+  const rootPath = resolveRoot(config.source_path, config.source_entry_path)
   const paths = sync(join(rootPath, glob))
   paths.forEach((path) => {
     const namespace = relative(join(rootPath), dirname(path))
@@ -55,10 +56,10 @@ const getEntryObject = () => {
 
 const getModulePaths = () => {
   const result = new ConfigList()
-  result.append('source', resolve(config.source_path))
-  result.append('node_modules', 'node_modules')
+  result.append('source', resolveRoot(config.source_path))
+  result.append('node_modules', join(root, 'node_modules'))
   if (config.resolved_paths) {
-    config.resolved_paths.forEach(path => result.append(basename(path), path))
+    config.resolved_paths.forEach(path => result.append(basename(path), resolveRoot(path)))
   }
   return result
 }
@@ -77,7 +78,7 @@ const getBaseConfig = () =>
     },
 
     resolveLoader: {
-      modules: ['node_modules']
+      modules: [join(root, 'node_modules')]
     },
 
     node: {

package/root.js

@@ -0,0 +1,11 @@
+const { resolve, join } = require('path')
+const root = process.env.RAILS_ROOT || '';
+const resolveRoot = (first, ...args) => first.startsWith('/')
+  ? join(first, ...args)
+  : resolve(root, first, ...args)
+
+
+module.exports = {
+  root,
+  resolveRoot
+}

test/test_app/config/webpacker.yml

@@ -0,0 +1,65 @@
+# Note: You must restart bin/webpack-dev-server for changes to take effect
+
+default: &default
+  source_path: app/javascript
+  source_entry_path: packs
+  public_output_path: packs
+  cache_path: tmp/cache/webpacker
+
+  # Additional paths webpack should lookup modules
+  # ['app/assets', 'engine/foo/app/assets']
+  resolved_paths:
+    - app/assets
+    - /etc/yarn
+
+  # Reload manifest.json on all requests so we reload latest compiled packs
+  cache_manifest: false
+
+  extensions:
+    - .coffee
+    - .erb
+    - .js
+    - .jsx
+    - .ts
+    - .vue
+    - .sass
+    - .scss
+    - .css
+    - .png
+    - .svg
+    - .gif
+    - .jpeg
+    - .jpg
+
+development:
+  <<: *default
+  compile: true
+
+  # Reference: https://webpack.js.org/configuration/dev-server/
+  dev_server:
+    https: false
+    host: localhost
+    port: 3035
+    public: localhost:3035
+    hmr: false
+    # Inline should be set to true if using HMR
+    inline: true
+    overlay: true
+    disable_host_check: true
+    use_local_ip: false
+
+test:
+  <<: *default
+  compile: true
+
+  # Compile test packs to a separate directory
+  public_output_path: packs-test
+
+production:
+  <<: *default
+
+  # Production depends on precompilation of packs prior to booting for performance.
+  compile: false
+
+  # Cache manifest.json for performance
+  cache_manifest: true

yarn.lock

@@ -1520,7 +1520,13 @@ date-now@^0.1.4:
   version "0.1.4"
   resolved "https://registry.yarnpkg.com/date-now/-/date-now-0.1.4.tgz#eaf439fd4d4848ad74e5cc7dbef200672b9e345b"
 
-debug@^2.2.0, debug@^2.6.8:
+debug@^2.2.0:
+  version "2.6.1"
+  resolved "https://registry.yarnpkg.com/debug/-/debug-2.6.1.tgz#79855090ba2c4e3115cc7d8769491d58f0491351"
+  dependencies:
+    ms "0.7.2"
+
+debug@^2.6.8:
   version "2.6.9"
   resolved "https://registry.yarnpkg.com/debug/-/debug-2.6.9.tgz#5d128515df134ff327e90a4c93f4e077a536341f"
   dependencies:
@@ -2296,7 +2302,18 @@ glob@^6.0.4:
     once "^1.3.0"
     path-is-absolute "^1.0.0"
 
-glob@^7.0.0, glob@^7.0.3, glob@^7.0.5, glob@^7.1.1, glob@^7.1.2, glob@~7.1.1:
+glob@^7.0.0, glob@^7.0.3, glob@^7.0.5:
+  version "7.1.1"
+  resolved "https://registry.yarnpkg.com/glob/-/glob-7.1.1.tgz#805211df04faaf1c63a3600306cdf5ade50b2ec8"
+  dependencies:
+    fs.realpath "^1.0.0"
+    inflight "^1.0.4"
+    inherits "2"
+    minimatch "^3.0.2"
+    once "^1.3.0"
+    path-is-absolute "^1.0.0"
+
+glob@^7.1.1, glob@^7.1.2, glob@~7.1.1:
   version "7.1.2"
   resolved "https://registry.yarnpkg.com/glob/-/glob-7.1.2.tgz#c19c9df9a028702d678612384a6552404c636d15"
   dependencies: