DOFVector test corrected for EIGEN backend

test/DOFVectorTest.cpp

@@ -22,10 +22,12 @@ void test_dofvector(B const& basis, DOFVector<B,T>& vec)
 
   vec = T(0);
   vec[0] = T(1);
+#if HAVE_MTL || HAVE_ISTL
   auto m0 = std::min_element(std::begin(vec.vector()), std::end(vec.vector()));
   auto m1 = std::max_element(std::begin(vec.vector()), std::end(vec.vector()));
   AMDIS_TEST( *m0 == T(0) );
   AMDIS_TEST( *m1 == T(1) );
+#endif
 
   // DOFVector models the concept of a VectorBackend in Dune::Functions
   static_assert(Dune::models<Dune::Functions::Concept::VectorBackend<B>, decltype(vec)>(), "");