async test for node 7

.travis.yml

@@ -1,6 +1,7 @@
 language: node_js
 node_js:
-  - "5"
+  - "7"
+  - "6"
   - "4"
   - "0.12"
   - "0.10"

test/async.js

@@ -0,0 +1,24 @@
+var browserify = require('../');
+var fs = require('fs');
+var vm = require('vm');
+var test = require('tap').test;
+
+var src = fs.readFileSync(__dirname + '/async/src.js','utf8');
+var canAsync = true;
+try { Function(src) } catch (err) { canAsync = false }
+
+if (!canAsync) console.error('# async/await unsupported in this environment')
+else test('async/await', function (t) {
+    t.plan(2);
+    var b = browserify(__dirname + '/async/src.js');
+    b.bundle(function (err, src) {
+        t.error(err)
+        var c = {
+            console: { log: log },
+            setTimeout: setTimeout,
+            clearTimeout: clearTimeout
+        }
+        vm.runInNewContext(src, c);
+        function log (msg) { t.equal(msg, 60) }
+    });
+});

test/async/src.js

@@ -0,0 +1,8 @@
+function f (x) { return new Promise(resolve => {
+  process.nextTick(() => { resolve(x) }) }) }
+
+async function add (x) {
+  return x + await f(20) + await f(30)
+}
+
+add(10).then(v => { console.log(v) })