diff --git a/tests/datetime/datetimetest.cpp b/tests/datetime/datetimetest.cpp
index e9e430998e..feddc48085 100644
--- a/tests/datetime/datetimetest.cpp
+++ b/tests/datetime/datetimetest.cpp
@@ -671,6 +671,10 @@ void DateTimeTestCase::TestTimeFormat()
                     case CompareTime:
                         CPPUNIT_ASSERT( dt.IsSameTime(dt2) );
                         break;
+
+                    case CompareNone:
+                        wxFAIL_MSG( _T("unexpected") );
+                        break;
                 }
             }
         }