add scope hositing test

Author: jescalan

test/fixtures/scope_hoisting/index.js

@@ -0,0 +1,3 @@
+import {something} from './util'
+
+something()

test/fixtures/scope_hoisting/util.js

@@ -0,0 +1,3 @@
+export function something () {
+  return 'wow'
+}

test/plugins.js

@@ -1,6 +1,7 @@
 const test = require('ava')
 const path = require('path')
 const EventEmitter = require('events')
+const webpack = require('webpack')
 const AfterPlugin = require('./fixtures/plugins/after_plugin')
 const {compileFixture, fs} = require('./_helpers')
 
@@ -18,3 +19,15 @@ test('compiles a project with a custom plugin, plugins can change output path',
     t.truthy(res.stats.compilation.options.entry.test === 'bar')
   })
 })
+
+test('works with scope hoisting', (t) => {
+  return compileFixture(t, 'scope_hoisting', {
+    entry: { main: './index.js' },
+    plugins: [new webpack.optimize.ModuleConcatenationPlugin()]
+  }).then(({res, publicPath}) => {
+    return fs.readFile(path.join(publicPath, 'main.js'), 'utf8')
+      .then((src) => {
+        t.regex(src, /\/\/ CONCATENATED MODULE: \.\/util\.js/)
+      })
+  })
+})