message: fix debug warning
diff: @@ -200,7 +200,7 @@ TEST_CASE("Convergence rate test on 2D NCMesh",
  a.RecoverFEMSolution(X, b, x);
  NewZienkiewiczZhuEstimator estimator(di, x);
  - const Vector &zzerr = estimator.GetLocalErrors();
  + estimator.GetLocalErrors();
  double error = estimator.GetTotalError();
  if (old_error > 0.0)
  