[tests][shallowater] use new neumann interface and fix warning for

frictionlaw in spatialparams

test/freeflow/shallowwater/roughchannel/problem.hh

@@ -119,6 +119,8 @@ class RoughChannelProblem : public ShallowWaterProblem<TypeTag>
     using FVGridGeometry = GetPropType<TypeTag, Properties::FVGridGeometry>;
     using NeumannFluxes = GetPropType<TypeTag, Properties::NumEqVector>;
     using ElementVolumeVariables = typename GetPropType<TypeTag, Properties::GridVolumeVariables>::LocalView;
+    using GridVariables = GetPropType<TypeTag, Properties::GridVariables>;
+    using ElementFluxVariablesCache = typename GridVariables::GridFluxVariablesCache::LocalView;
     using VolumeVariables = typename ElementVolumeVariables::VolumeVariables;
     using FVElementGeometry = typename GetPropType<TypeTag, Properties::FVGridGeometry>::LocalView;
     using SubControlVolumeFace = typename FVElementGeometry::SubControlVolumeFace;
@@ -287,6 +289,7 @@ public:
     NeumannFluxes neumann(const Element& element,
                           const FVElementGeometry& fvGeometry,
                           const ElementVolumeVariables& elemVolVars,
+                          const ElementFluxVariablesCache& elemFluxVarsCache,
                           const SubControlVolumeFace& scvf) const
     {
         NeumannFluxes values(0.0);

test/freeflow/shallowwater/roughchannel/spatialparams.hh

@@ -70,7 +70,7 @@ public:
           Scalar manningN = getParam<Scalar>("Problem.ManningN");
           frictionLaw_ = std::make_unique<FrictionLawManning<VolumeVariables>>(gravity_, manningN);
       }
-      if (frictionLawType_ == "Nikuradse")
+      else if (frictionLawType_ == "Nikuradse")
       {
           Scalar ks = getParam<Scalar>("Problem.Ks"); // equivalent sand roughness
           frictionLaw_ = std::make_unique<FrictionLawNikuradse<VolumeVariables>>(ks);