diff --git a/test/header-test.js b/test/header-test.js
new file mode 100644
index 0000000..6bc8b8e
--- /dev/null
+++ b/test/header-test.js
@@ -0,0 +1,36 @@
+var assert = require('assert'),
+    request = require('request'),
+    vows = require('vows'),
+    union = require('../');
+
+vows.describe('union/header').addBatch({
+  'When using `union`': {
+    'with a server that responds with a header': {
+      topic: function () {
+        var callback = this.callback;
+        var server = union.createServer({
+          before: [
+            function (req, res) {
+              res.on('header', function() {
+                callback(null, res);
+              });
+              res.writeHead(200, { 'content-type': 'text' });
+              res.end();
+            }
+          ]
+        });
+        server.listen(9092, function() {
+          request('http://localhost:9092/');
+        });
+      },
+      'it should have proper `headerSent` set': function (err, res) {
+        assert.isNull(err);
+        assert.isTrue(res.headerSent);
+      },
+      'it should have proper `_emittedHeader` set': function (err, res) {
+        assert.isNull(err);
+        assert.isTrue(res._emittedHeader);
+      }
+    }
+  }
+}).export(module);