Start implementing general unit test for the dune-istl matrix interface

... and use it to test the BCRSMatrix class.

Currently, the new test only tests the vector space operations
required of a dune-istl matrix.  More is to come in subsequent
patches.

dune/istl/test/CMakeLists.txt

-# install the test tools as we want to support testing 3rd-party vectors with an installed dune-istl
+# install the test tools as we want to support testing 3rd-party vectors and matrices with an installed dune-istl
 install(FILES
+        matrixtest.hh
         vectortest.hh
         laplacian.hh
         multirhstest.hh
@@ -7,6 +8,8 @@ install(FILES
 
 dune_add_test(SOURCES bcrsassigntest.cc)
 
+dune_add_test(SOURCES bcrsmatrixtest.cc)
+
 dune_add_test(SOURCES bcrsnormtest.cc)
 
 dune_add_test(SOURCES cgconditiontest.cc)

dune/istl/test/bcrsmatrixtest.cc

+// -*- tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+// vi: set et ts=4 sw=2 sts=2:
+#include "config.h"
+
+#include <dune/common/fmatrix.hh>
+#include <dune/common/fvector.hh>
+#include <dune/common/float_cmp.hh>
+
+#include <dune/istl/bvector.hh>
+#include <dune/istl/test/laplacian.hh>
+#include <dune/istl/test/matrixtest.hh>
+
+using namespace Dune;
+
+template <class Matrix, class Vector>
+int testBCRSMatrix(int size)
+{
+  // Set up a test matrix
+  Matrix mat;
+  setupLaplacian(mat, size);
+
+  // Test vector space operations
+  testVectorSpaceOperations(mat);
+
+  return 0;
+}
+
+int main(int argc, char** argv)
+{
+  // Test block matrices and vectors with trivial blocks
+  int ret = testBCRSMatrix<BCRSMatrix<FieldMatrix<double,1,1> >, BlockVector<FieldVector<double,1> > >(10);
+
+  return ret;
+}

dune/istl/test/matrixtest.hh

+// -*- tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+// vi: set et ts=4 sw=2 sts=2:
+#ifndef DUNE_ISTL_TEST_MATRIXTEST_HH
+#define DUNE_ISTL_TEST_MATRIXTEST_HH
+
+/** \file
+ * \brief Infrastructure for testing the dune-istl matrix interface
+ *
+ * This file contains various methods that test parts of the dune-istl matrix interface.
+ * They only test very general features, i.e., features that every dune-istl matrix should
+ * have.
+ *
+ * At the same time, these tests should help to define what the dune-istl matrix interface
+ * actually is.  They may not currently define the entire interface, but they are a lower
+ * bound: any feature that is tested here is part of the dune-istl matrix interface.
+ */
+
+#include <dune/common/exceptions.hh>
+#include <dune/common/test/iteratortest.hh>
+
+namespace Dune
+{
+  template <typename Matrix>
+  void testVectorSpaceOperations(const Matrix& m)
+  {
+    // Make a mutable copy of the argument
+    Matrix mMutable = m;
+
+    // operator+=
+    mMutable += m;
+    // operator-=
+    mMutable -= m;
+
+    // operator*=
+    mMutable *= 0.5;
+
+    // operator/=
+    mMutable /= 0.5;
+
+    // axpy -- not sure whether that really is an interface method
+    //mMutable.axpy(0.5,m);
+  }
+
+}  // namespace Dune
+
+#endif