Adds test showing ES6 circular dependencies working with Babel

test/circular/bar.js

@@ -0,0 +1,7 @@
+import { getBar, name as fooName } from './foo';
+
+export let name = 'bar';
+
+export function getFoo() {
+	return fooName;
+}

test/circular/dev.html

@@ -0,0 +1,3 @@
+<script src="../../bower_components/steal/steal.js"
+		base-url="./"
+		config="package.json!npm"></script>

test/circular/foo.js

@@ -0,0 +1,7 @@
+import { getFoo, name as barName } from './bar';
+
+export let name = 'foo';
+
+export function getBar() {
+	return barName;
+}

test/circular/main.js

@@ -0,0 +1,6 @@
+import { getBar } from './foo';
+import { getFoo } from './bar';
+
+// true in dev, false in production
+window.circularWorks = (getBar() === 'bar') &&
+	(getFoo() === 'foo');

test/circular/package.json

@@ -0,0 +1,8 @@
+{
+	"name": "circular",
+	"main": "main.js",
+	"version": "1.0.0",
+	"system": {
+		"transpiler": "babel"
+	}
+}

test/circular/prod.html

@@ -0,0 +1,5 @@
+<script src="../../bower_components/steal/steal.js"
+		base-url="./"
+		config="package.json!npm"
+		main="circular/main"
+		env="production"></script>

test/multibuild_test.js

@@ -918,7 +918,28 @@ describe("multi build", function(){
 		});
 	});
 
+	it("Circular refs works with Babel", function(done){
+		rmdir(__dirname+"/circular/dist", function(error){
+			if(error){
+				done(error);
+				return;
+			}
 
+			multiBuild({
+				config: __dirname+"/circular/package.json!npm",
+			}, {
+				quiet: true,
+				minify: false
+			}).then(function(){
+				open("test/circular/prod.html",function(browser, close){
+					find(browser,"circularWorks", function(result){
+						assert.equal(result, true, "circular refs worked");
+						close();
+					}, close);
+				}, done);
+			}, done);
+		});
+	});
 
 	describe("with plugins", function(){
 		this.timeout(60000);