[tests] Test objects in namespace GeometryTypes

dune/geometry/test/test-constexpr-geometrytype.cc

@@ -7,5 +7,11 @@
 int main ( int argc, char **argv )
 {
   constexpr auto gt_none_1 = Dune::GeometryType();
-  return not std::integral_constant<bool,gt_none_1.isNone()>{};
+  constexpr auto gt_none_2 = Dune::GeometryTypes::none(0);
+  return not std::integral_constant<
+    bool,
+    gt_none_1.isNone()
+    and gt_none_1 == gt_none_2
+    and Dune::GeometryType(1,1) == Dune::GeometryTypes::line
+    >{};
 }