[test] Add unit test for sequential linear solver

test/CMakeLists.txt

@@ -2,6 +2,7 @@ add_subdirectory(common)
 add_subdirectory(geomechanics)
 add_subdirectory(freeflow)
 add_subdirectory(io)
+add_subdirectory(linear)
 add_subdirectory(material)
 add_subdirectory(multidomain)
 add_subdirectory(nonlinear)

test/linear/CMakeLists.txt

+dune_symlink_to_source_files(FILES "params.input")
+dumux_add_test(NAME test_linearsolver
+               SOURCES test_linearsolver.cc
+               LABELS linear unit)

test/linear/params.input

+TestSolver = CG
+ProblemSize = 2
+
+[CG.LinearSolver]
+Type = cgsolver
+Preconditioner.Type = amg

test/linear/test_linearsolver.cc

+#include <config.h>
+
+#include <iostream>
+#include <iomanip>
+#include <cmath>
+
+#include <dumux/common/parameters.hh>
+#include <dumux/discretization/method.hh>
+#include <dumux/linear/linearsolvertraits.hh>
+//#include <dumux/linear/istlsolverfactorybackend.hh>
+#include <dumux/linear/amgbackend.hh>
+
+#include <dune/common/exceptions.hh>
+#include <dune/common/fvector.hh>
+#include <dune/common/fmatrix.hh>
+
+#include <dune/grid/common/mcmgmapper.hh>
+#include <dune/grid/yaspgrid.hh>
+
+#include <dune/istl/bvector.hh>
+#include <dune/istl/bcrsmatrix.hh>
+
+#include <dune/istl/test/laplacian.hh>
+#include <dune/istl/paamg/test/anisotropic.hh>
+
+namespace Dumux::Test {
+
+struct MockGridGeometry
+{
+    using GridView = Dune::YaspGrid<2>::LeafGridView;
+    using DofMapper = Dune::MultipleCodimMultipleGeomTypeMapper<GridView>;
+    using VertexMapper = Dune::MultipleCodimMultipleGeomTypeMapper<GridView>;
+    static constexpr auto discMethod = DiscretizationMethod::box;
+};
+
+} // end namespace Dumux::Test
+
+int main(int argc, char* argv[]) try
+{
+    using namespace Dumux;
+
+    Dune::MPIHelper::instance(argc, argv);
+
+    Parameters::init(argc, argv, "params.input");
+
+    using Vector = Dune::BlockVector<Dune::FieldVector<double, 2>>;
+    using Matrix = Dune::BCRSMatrix<Dune::FieldMatrix<double, 2, 2>>;
+
+    // create matrix & vectors (we want to solve Ax=b)
+    Matrix A; const int numDofs = getParam<int>("ProblemSize");
+    setupLaplacian(A, numDofs);
+
+    Vector x(A.N()); Vector b(A.M());
+    x = 0; b = 1;
+
+    using LinearSolverTraits = Dumux::LinearSolverTraits<Test::MockGridGeometry>;
+    using LinearSolver = AMGBiCGSTABBackend<LinearSolverTraits>;
+
+    const auto testSolverName = getParam<std::string>("TestSolver");
+    LinearSolver solver(testSolverName);
+
+    solver.solve(A, x, b);
+    if (!solver.result().converged)
+      DUNE_THROW(Dune::Exception, testSolverName << " did not converge!");
+
+    return 0;
+}
+catch (const Dune::Exception& e)
+{
+    std::cout << e << std::endl;
+    return 1;
+}