Added failing test for inclusion of internally used default export

test/function/includes-internally-used-default-export/_config.js

@@ -0,0 +1,3 @@
+module.exports = {
+	description: 'includes default exports that are only used internally'
+};

test/function/includes-internally-used-default-export/main.js

@@ -0,0 +1,3 @@
+import { b } from './module.js';
+
+assert.equal(b(), 15);

test/function/includes-internally-used-default-export/module.js

@@ -0,0 +1,7 @@
+export default function a() {
+  return 5;
+}
+
+export function b() {
+  return a() + 10;
+}