fix gcc compilation warning

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@42584 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

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;
                 }
             }
         }