message: Add a use case of the optional pattern string in IOManager::write
diff: @@ -113,7 +113,7 @@ TEST(spio_parallel, parallel_writeread)
  const std::string file_name = "out_spio_parallel_write_read";
  - writer.write(root, num_files, file_name, PROTOCOL);
  + writer.write(root, num_files, file_name, PROTOCOL, "tree_%07d");
  std::string root_name = file_name + ROOT_EXT;
  // _parallel_io_save_end
  @@ -159,8 +159,14 @@ TEST(spio_parallel, parallel_writeread)
  if ( (my_rank == 1 || num_ranks == 1) && PROTOCOL == "sidre_hdf5" )
  {
  - conduit::Node n;
  - conduit::relay::io::load(root_name + ":extra", "hdf5", n);
  + conduit::Node root_node;
  + conduit::relay::io::load(root_name, "hdf5", root_node);
  +
  + std::string pattern = root_node["tree_pattern"].as_string();
  +
  + const conduit::Node& n = root_node["extra"];
  +
  + EXPECT_EQ(pattern, "tree_%07d");
  double dval = n["dval"].to_double();
  