Add failing test case.

test/function/assignment-to-re-exports/_config.js

@@ -0,0 +1,10 @@
+var assert = require( 'assert' );
+
+module.exports = {
+	description: 're-exports are kept up-to-date',
+	exports: function ( exports ) {
+		assert.equal( exports.count, 0 );
+		exports.incr();
+		assert.equal( exports.count, 1 );
+	}
+};

test/function/assignment-to-re-exports/count.js

@@ -0,0 +1,5 @@
+export var count = 0;
+
+export function incr () {
+	count += 1;
+}

test/function/assignment-to-re-exports/main.js

@@ -0,0 +1 @@
+export {count, incr} from './count';