[test] Add test for reading vtk polylines with multiple points

test/io/vtk/CMakeLists.txt

 add_input_file_links()
+dune_symlink_to_source_files(FILES polyline.vtp)
 
 dune_add_test(NAME test_vtkreader_3d
               SOURCES test_vtkreader.cc
@@ -53,6 +54,15 @@ dune_add_test(NAME test_vtkreader_1d
                        --files ${CMAKE_SOURCE_DIR}/test/references/test_md_embedded1d3d_1p_richards_tpfatpfa_1d-reference.vtp
                                ${CMAKE_CURRENT_BINARY_DIR}/test-1d.vtp)
 
+dune_add_test(NAME test_vtkreader_1d_polyline
+              TARGET test_vtkreader_1d
+              LABELS unit io
+              COMMAND ${CMAKE_SOURCE_DIR}/bin/testing/runtest.py
+              CMD_ARGS --script fuzzy
+                       --command "${CMAKE_CURRENT_BINARY_DIR}/test_vtkreader_1d polyline.vtp test_polyline"
+                       --files ${CMAKE_SOURCE_DIR}/test/references/test_vtkreader_1d_polyline-reference.vtp
+                               ${CMAKE_CURRENT_BINARY_DIR}/test_polyline.vtp)
+
 dune_add_test(NAME test_vtk_staggeredfreeflowpvnames
               SOURCES test_vtk_staggeredfreeflowpvnames.cc
               LABELS unit io)

test/io/vtk/polyline.vtp

+<?xml version="1.0"?>
+<VTKFile type="PolyData" version="0.1" byte_order="LittleEndian">
+  <PolyData>
+    <Piece NumberOfLines="1" NumberOfPoints="21">
+      <CellData Scalars="p">
+        <DataArray type="Float32" Name="p" NumberOfComponents="1" format="ascii">
+          1
+        </DataArray>
+        <DataArray type="Float32" Name="process rank" NumberOfComponents="1" format="ascii">
+          0
+        </DataArray>
+      </CellData>
+      <PointData Scalars="r">
+        <DataArray type="Float32" Name="r" NumberOfComponents="1" format="ascii">
+          0.05 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 2.0
+        </DataArray>
+      </PointData>
+      <Points>
+        <DataArray type="Float32" Name="Coordinates" NumberOfComponents="3" format="ascii">
+          0 0 0 0 0 0.05 0 0 0.1 0 0 0.15
+          0 0 0.2 0 0 0.25 0 0 0.3 0 0 0.35
+          0 0 0.4 0 0 0.45 0 0 0.5 0 0 0.55
+          0 0 0.6 0 0 0.65 0 0 0.7 0 0 0.75
+          0 0 0.8 0 0 0.85 0 0 0.9 0 0 0.95
+          0 0 1
+        </DataArray>
+      </Points>
+      <Lines>
+        <DataArray type="Int32" Name="connectivity" NumberOfComponents="1" format="ascii">
+          0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
+        </DataArray>
+        <DataArray type="Int32" Name="offsets" NumberOfComponents="1" format="ascii">
+          21
+        </DataArray>
+      </Lines>
+    </Piece>
+  </PolyData>
+</VTKFile>

test/references/test_vtkreader_1d_polyline-reference.vtp

+<?xml version="1.0"?>
+<VTKFile type="PolyData" version="0.1" byte_order="LittleEndian">
+  <PolyData>
+    <Piece NumberOfLines="20" NumberOfPoints="21">
+      <PointData Scalars="r">
+        <DataArray type="Float32" Name="r" NumberOfComponents="1" format="ascii">
+          0.05 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 1.1
+          1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 2
+        </DataArray>
+      </PointData>
+      <CellData Scalars="p">
+        <DataArray type="Float32" Name="p" NumberOfComponents="1" format="ascii">
+          1 1 1 1 1 1 1 1 1 1 1 1
+          1 1 1 1 1 1 1 1
+        </DataArray>
+        <DataArray type="Float32" Name="process rank" NumberOfComponents="1" format="ascii">
+          0 0 0 0 0 0 0 0 0 0 0 0
+          0 0 0 0 0 0 0 0
+        </DataArray>
+      </CellData>
+      <Points>
+        <DataArray type="Float32" Name="Coordinates" NumberOfComponents="3" format="ascii">
+          0 0 0 0 0 0.05 0 0 0.1 0 0 0.15
+          0 0 0.2 0 0 0.25 0 0 0.3 0 0 0.35
+          0 0 0.4 0 0 0.45 0 0 0.5 0 0 0.55
+          0 0 0.6 0 0 0.65 0 0 0.7 0 0 0.75
+          0 0 0.8 0 0 0.85 0 0 0.9 0 0 0.95
+          0 0 1
+        </DataArray>
+      </Points>
+      <Lines>
+        <DataArray type="Int32" Name="connectivity" NumberOfComponents="1" format="ascii">
+          0 1 1 2 2 3 3 4 4 5 5 6
+          6 7 7 8 8 9 9 10 10 11 11 12
+          12 13 13 14 14 15 15 16 16 17 17 18
+          18 19 19 20
+        </DataArray>
+        <DataArray type="Int32" Name="offsets" NumberOfComponents="1" format="ascii">
+          2 4 6 8 10 12 14 16 18 20 22 24
+          26 28 30 32 34 36 38 40
+        </DataArray>
+      </Lines>
+    </Piece>
+  </PolyData>
+</VTKFile>