message: Add the double upgrade test
diff: @@ -161,6 +161,34 @@ function get_node_protocol_version()
  sed -e 's/^"//' -e 's/"$//'
  }
  +#######################################
  +# Returns the lowest complete block the node has.
  +# Arguments:
  +# Node ordinal identifier.
  +#######################################
  +function get_node_lowest_available_block()
  +{
  + local NODE_ID=${1}
  +
  + echo $(get_node_status "$NODE_ID") | \
  + jq '.available_block_range.low' | \
  + sed -e 's/^"//' -e 's/"$//'
  +}
  +
  +#######################################
  +# Returns the highest complete block the node has.
  +# Arguments:
  +# Node ordinal identifier.
  +#######################################
  +function get_node_highest_available_block()
  +{
  + local NODE_ID=${1}
  +
  + echo $(get_node_status "$NODE_ID") | \
  + jq '.available_block_range.high' | \
  + sed -e 's/^"//' -e 's/"$//'
  +}
  +
  #######################################
  # Returns protocol version being run by a node by inspecting it's bin folder.
  # Arguments:
  