add es6 support and tests - ref gulpjs/gulp#830

package.json

@@ -28,7 +28,7 @@
     "archy": "^1.0.0",
     "chalk": "^0.5.0",
     "gulp-util": "^3.0.0",
-    "interpret": "^0.3.2",
+    "interpret": "^0.4.1",
     "liftoff": "^1.0.0",
     "minimist": "^1.1.0",
     "pretty-hrtime": "^0.2.0",
@@ -37,6 +37,7 @@
     "v8flags": "^1.0.1"
   },
   "devDependencies": {
+    "6to5": "^2.9.4",
     "code": "^1.2.1",
     "coveralls": "^2.7.0",
     "gulp": ">=3.8.10",

test/es6.js

@@ -0,0 +1,17 @@
+'use strict';
+
+var lab = exports.lab = require('lab').script();
+var code = require('code');
+
+var child = require('child_process');
+
+lab.experiment('es6', function () {
+
+  lab.test('supports es6', function (done) {
+    child.exec('node ' + __dirname + '/../bin/gulp.js --cwd ./test --gulpfile test/gulpfile.es6', function(err, stdout) {
+      code.expect(stdout).to.contain('Requiring external module 6to5/register');
+      done(err);
+    });
+  });
+
+});

test/gulpfile.es6

@@ -0,0 +1,9 @@
+'use strict';
+
+var gulp = require('gulp');
+
+gulp.task('test1', () => {});
+gulp.task('test2', () => {});
+gulp.task('test3', () => {});
+
+gulp.task('default', () => {});