Add a test.

diff --git a/tests/lac/block_matrices_07.cc b/tests/lac/block_matrices_07.cc
new file mode 100644 (file)
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+++ b/tests/lac/block_matrices_07.cc
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+// ---------------------------------------------------------------------
+//
+// Copyright (C) 2000 - 2021 by the deal.II authors
+//
+// This file is part of the deal.II library.
+//
+// The deal.II library is free software; you can use it, redistribute
+// it, and/or modify it under the terms of the GNU Lesser General
+// Public License as published by the Free Software Foundation; either
+// version 2.1 of the License, or (at your option) any later version.
+// The full text of the license can be found in the file LICENSE.md at
+// the top level directory of deal.II.
+//
+// ---------------------------------------------------------------------
+
+// It was not possible to compare non-const iterators into block
+// sparse matrices because we declared the wrong class as a
+// friend. This test checks that this is fixed.
+
+#include <deal.II/base/function.h>
+#include <deal.II/base/quadrature_lib.h>
+
+#include <deal.II/lac/block_sparse_matrix.h>
+
+#include "../tests.h"
+
+#include "../testmatrix.h"
+
+
+dealii::BlockSparseMatrix<double> systemMatrix;
+int
+main()
+{
+  initlog();
+
+  const unsigned int size = 5;
+  unsigned int       dim  = (size - 1) * (size - 1);
+
+  FDMatrix testproblem(size, size);
+
+  BlockSparsityPattern block_structure(1, 1);
+  block_structure.block(0, 0).reinit(dim, dim, 5);
+  block_structure.collect_sizes();
+  testproblem.five_point_structure(block_structure.block(0, 0));
+  block_structure.compress();
+  BlockSparseMatrix<double> block_A(block_structure);
+
+  auto block_AIteratorEnd = block_A.end(0);
+
+  auto block_AIteratorBegin = block_A.begin(0);
+
+  if (block_AIteratorBegin != block_AIteratorEnd)
+    deallog << "Not equal" << std::endl;
+
+  deallog << "OK." << std::endl;
+}

diff --git a/tests/lac/block_matrices_07.output b/tests/lac/block_matrices_07.output
new file mode 100644 (file)
index 0000000..39300ad
--- /dev/null
+++ b/tests/lac/block_matrices_07.output
@@ -0,0 +1,3 @@
+
+DEAL::Not equal
+DEAL::OK.