chore(*) add gulp build --env test

You can build your app with the test configuration (using stubs/mocks ...)
Just use `gulp build --env test`
Like all the `gulp build` tasks:
* Your bundled app will land in `build/dist` folder
* You'll be able to launch it via `gulp serve --env prod` (yeah it's a bit tricky but you
understand)

gulp/tasks/scripts.js

@@ -4,8 +4,10 @@ import util from 'gulp-util';
 import gulp from 'gulp';
 import jshint from 'gulp-jshint';
 import cache from 'gulp-cache';
+import footer from 'gulp-footer';
+import gulpif from 'gulp-if';
 
-import {ENV} from '../utils.js';
+import {LOG,COLORS,ENV} from '../utils.js';
 import paths from '../paths';
 
 /**
@@ -32,17 +34,30 @@ gulp.task('jshint', () => {
     .pipe(jshint.reporter('fail'));
 });
 
+gulp.task('jspmconfig', () => {
+  var injection;
+  if(ENV === 'test'){
+    var jspmOverride = require(paths.test.config.jspmOverride);
+    LOG(COLORS.yellow('[INFOS] Using jspm.override.json:'))
+    var injection = "System.config("+JSON.stringify(jspmOverride)+")";
+    LOG(COLORS.yellow(injection));
+  }
+  return gulp.src(paths.config.jspm)
+    .pipe(gulpif(ENV === 'test', footer(injection)))
+    .pipe(gulp.dest(paths.tmp.config.basePath));
+});
+
 /**
  * Create JS production bundle.
  */
-gulp.task('bundle', ['jshint'], (cb) => {
+gulp.task('bundle', ['jshint', 'jspmconfig'], (cb) => {
   const Builder = require('systemjs-builder');
   const builder = new Builder();
   const inputPath = 'src/app/bootstrap';
   const outputFile = paths.tmp.scripts + 'app.bootstrap.build.js';
   const outputOptions = {sourceMaps: true, config: {sourceRoot: paths.tmp.scripts}};
 
-  builder.loadConfig('./jspm.config.js')
+  builder.loadConfig(paths.tmp.config.jspm)
     .then(() => {
       builder.buildSFX(inputPath, outputFile, outputOptions)
         .then(() => {

package.json

@@ -71,6 +71,7 @@
     "gulp-footer": "^1.0.5",
     "gulp-header": "^1.2.2",
     "gulp-htmlhint": "^0.3.0",
+    "gulp-if": "^1.2.5",
     "gulp-imagemin": "^2.3.0",
     "gulp-inject": "^1.5.0",
     "gulp-jshint": "^1.11.0",