diff --git a/tests/filename/filenametest.cpp b/tests/filename/filenametest.cpp
index 7e85380c1b..eefd5ffd62 100644
--- a/tests/filename/filenametest.cpp
+++ b/tests/filename/filenametest.cpp
@@ -28,15 +28,7 @@
     #include "wx/msw/registry.h"
 #endif // __WXMSW__
 
-// ----------------------------------------------------------------------------
-// local functions
-// ----------------------------------------------------------------------------
-
-// define stream inserter for wxFileName to use it in CPPUNIT_ASSERT_EQUAL()
-inline std::ostream& operator<<(std::ostream& o, const wxFileName& fn)
-{
-    return o << fn.GetFullPath();
-}
+#include "testfile.h"
 
 // ----------------------------------------------------------------------------
 // test data
diff --git a/tests/testfile.h b/tests/testfile.h
index d982ee9334..6946c8a10f 100644
--- a/tests/testfile.h
+++ b/tests/testfile.h
@@ -13,6 +13,14 @@
 #include "wx/filefn.h"
 #include "wx/filename.h"
 
+#include <ostream>
+
+// define stream inserter for wxFileName to use it in CPPUNIT_ASSERT_EQUAL()
+inline std::ostream& operator<<(std::ostream& o, const wxFileName& fn)
+{
+    return o << fn.GetFullPath();
+}
+
 // ----------------------------------------------------------------------------
 // TestFile: self deleting test file in temporary directory
 // ----------------------------------------------------------------------------