feat: support dynamic import in jest tests (close #922)

packages/@vue/babel-preset-app/index.js

@@ -27,6 +27,8 @@ module.exports = (context, options = {}) => {
   // cli-plugin-jest sets this to true because Jest runs without bundling
   if (process.env.VUE_CLI_BABEL_TRANSPILE_MODULES) {
     envOptions.modules = 'commonjs'
+    // necessary for dynamic import to work in tests
+    plugins.push(require('babel-plugin-dynamic-import-node'))
   }
 
   // pass options along to babel-preset-env

packages/@vue/babel-preset-app/package.json

@@ -27,6 +27,7 @@
     "@babel/preset-stage-2": "^7.0.0-0",
     "@babel/runtime": "^7.0.0-0",
     "babel-helper-vue-jsx-merge-props": "^2.0.3",
+    "babel-plugin-dynamic-import-node": "^1.2.0",
     "babel-plugin-jsx-event-modifiers": "^2.0.5",
     "babel-plugin-jsx-v-model": "^2.0.3",
     "babel-plugin-transform-vue-jsx": "^3.5.1"

yarn.lock

@@ -1189,6 +1189,12 @@ babel-messages@^6.23.0:
   dependencies:
     babel-runtime "^6.22.0"
 
+babel-plugin-dynamic-import-node@^1.2.0:
+  version "1.2.0"
+  resolved "https://registry.yarnpkg.com/babel-plugin-dynamic-import-node/-/babel-plugin-dynamic-import-node-1.2.0.tgz#f91631e703e0595e47d4beafbb088576c87fbeee"
+  dependencies:
+    babel-plugin-syntax-dynamic-import "^6.18.0"
+
 babel-plugin-istanbul@^4.1.4, babel-plugin-istanbul@^4.1.5:
   version "4.1.5"
   resolved "https://registry.yarnpkg.com/babel-plugin-istanbul/-/babel-plugin-istanbul-4.1.5.tgz#6760cdd977f411d3e175bb064f2bc327d99b2b6e"
@@ -1213,6 +1219,10 @@ babel-plugin-jsx-v-model@^2.0.3:
     html-tags "^2.0.0"
     svg-tags "^1.0.0"
 
+babel-plugin-syntax-dynamic-import@^6.18.0:
+  version "6.18.0"
+  resolved "https://registry.yarnpkg.com/babel-plugin-syntax-dynamic-import/-/babel-plugin-syntax-dynamic-import-6.18.0.tgz#8d6a26229c83745a9982a441051572caa179b1da"
+
 babel-plugin-syntax-jsx@^6.18.0:
   version "6.18.0"
   resolved "https://registry.yarnpkg.com/babel-plugin-syntax-jsx/-/babel-plugin-syntax-jsx-6.18.0.tgz#0af32a9a6e13ca7a3fd5069e62d7b0f58d0d8946"