public void Can_calculate_node_index_from_row_and_index_at_row(uint row, uint indexAtRow, ulong?nodeIndex)
 {
     if (nodeIndex == null)
     {
         Assert.Throws <ArgumentOutOfRangeException>(() => BaselineTree.GetNodeIndex(row, indexAtRow));
     }
     else
     {
         BaselineTree.GetNodeIndex(row, indexAtRow).Should().Be(nodeIndex.Value);
     }
 }