only run test checking whether FileVTK can load volume meshes if open volume mesh exists

git-svn-id: http://www.openflipper.org/svnrepo/OpenFlipper/branches/Free@16432 383ad7c9-94d9-4d36-a494-682f7c89f535

PluginCollection-FilePlugins/Plugin-FileVTK/tests/CMakeLists.txt

@@ -11,6 +11,8 @@ if(BUILD_TESTING)
   # ========================================================================
   run_single_object_file_mesh_test("filevtk" "Plugin-FileVTK/triangle_mesh_ascii.vtk" "fileMeshTest.ofs")
 
-  run_single_object_file_mesh_test("filevtk" "Plugin-FileVTK/vtk_ascii_volume_mesh_test_file.vtk" "fileVolumeMeshTest.ofs")
+  if (EXISTS ${CMAKE_SOURCE_DIR}/ObjectTypes/PolyhedralMesh)
+    run_single_object_file_mesh_test("filevtk" "Plugin-FileVTK/vtk_ascii_volume_mesh_test_file.vtk" "fileVolumeMeshTest.ofs")
+  endif ()
 
 endif()