diff --git a/testing/fx_string_testhelpers.cpp b/testing/fx_string_testhelpers.cpp
new file mode 100644
index 0000000..443cc89
--- /dev/null
+++ b/testing/fx_string_testhelpers.cpp
@@ -0,0 +1,18 @@
+// Copyright 2014 PDFium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "testing/fx_string_testhelpers.h"
+
+#include <iomanip>
+#include <ios>
+#include <string>
+
+std::ostream& operator<<(std::ostream& os, const CFX_DateTime& dt) {
+  os << dt.GetYear() << "-" << std::to_string(dt.GetMonth()) << "-"
+     << std::to_string(dt.GetDay()) << " " << std::to_string(dt.GetHour())
+     << ":" << std::to_string(dt.GetMinute()) << ":"
+     << std::to_string(dt.GetSecond()) << "."
+     << std::to_string(dt.GetMillisecond());
+  return os;
+}