diff --git a/tests/strings/hexconv.cpp b/tests/strings/hexconv.cpp
index f9b8a24200..00e8c1404d 100644
--- a/tests/strings/hexconv.cpp
+++ b/tests/strings/hexconv.cpp
@@ -85,7 +85,7 @@ void HexConvTestCase::DecToHex2()
 
         CPPUNIT_ASSERT_EQUAL( hexStr[0], (wxChar)szHexStrRef[0] );
         CPPUNIT_ASSERT_EQUAL( hexStr[1], (wxChar)szHexStrRef[1] );
-        CPPUNIT_ASSERT_EQUAL( hexStr[2], wxS('\0') );
+        CPPUNIT_ASSERT_EQUAL( hexStr[2], (wxChar)'\0' );
         CPPUNIT_ASSERT_EQUAL( hexStr[3], c3 );
     }
 }