[components] Derive Air component from base and gas

dumux/material/components/air.hh

@@ -40,7 +40,8 @@ namespace Components {
  * \tparam Scalar The type used for scalar values
  */
 template <class Scalar>
-class Air : public Component<Scalar, Air<Scalar> >
+class Air : public Components::Base<Scalar, Air<Scalar> >,
+            public Components::Gas<Scalar, Air<Scalar> >
 {
     using IdealGas = Dumux::IdealGas<Scalar>;
 

test/material/components/CMakeLists.txt

-dune_add_test(SOURCES test_componenttraits.cc)
+dune_add_test(SOURCES test_componenttraits.cc
+              COMPILE_ONLY)
 
 add_executable(plot_component plotproperties.cc)
 

test/material/components/test_componenttraits.cc

@@ -35,6 +35,7 @@ int main(int argc, char *argv[])
 
     using Traits = ComponentTraits<Components::Air<double>>;
     static_assert(Traits::hasGasState, "Air component is reported to have no gas state?!");
-    // static_assert(!Traits::hasSolidState, "Air component is reported to implement a solid state?!");
+    static_assert(!Traits::hasSolidState, "Air component is reported to implement a solid state?!");
+    static_assert(!Traits::hasLiquidState, "Air component is reported to implement a liquid state?!");
     static_assert(std::is_same<double, Traits::Scalar>::value, "Scalar type not correctly reported!");
 }