fix(karma): throws when vue warns

Author: Walker Leite

template/package.json

@@ -78,6 +78,7 @@
     "loopback-chai": "^2.3.0",
     "mocha": "^3.4.2",
     "sinon": "^2.3.8",
+    "through2": "^2.0.3",
     "tmp": "0.0.33",
     "vinyl-buffer": "^1.0.0",
     "vinyl-source-stream": "^1.1.0",

template/test/karma.conf.js

@@ -2,11 +2,27 @@ import babelify from 'babelify';
 import vueify from 'vueify';
 import modulesify from 'css-modulesify';
 import tmp from 'tmp';
+import through from 'through2';
 import {dirs} from '../gulp-tasks/config';
 import {customSass} from '../gulp-tasks/compilers';
 
 const cssBundleFile = tmp.fileSync();
 
+// Just hook window.console to throw vue warn
+const consoleAppendfy = () => through(function (buf, enc, next) {
+  const hook = `
+    const error = console.error;
+    console.error = function(warning, ...args) {
+      if (/(Vue warn)/.test(warning)) {
+        throw new Error(warning);
+      }
+      error.apply(console, [warning, ...args]);
+    };
+  `;
+  this.push(hook + buf.toString('utf8'));
+  next();
+});
+
 export default (config) => {
   vueify.compiler.applyConfig({
     sass: {
@@ -31,7 +47,7 @@ export default (config) => {
     browserify: {
       output: cssBundleFile.name,
       debug: true,
-      transform: [babelify, vueify],
+      transform: [consoleAppendfy, babelify, vueify],
       plugin: [[modulesify, {
         global: true,
         generateScopedName(name, filename) {