message: Fix test container default behavior
  If the test-container receives no argument via CLI it just sleeps
  forever.
diff: @@ -24,6 +24,12 @@ use std::{
  };
  use structopt::StructOpt;
  +#[derive(Debug, StructOpt)]
  +struct Opt {
  + #[structopt(subcommand)]
  + command: Option<Command>,
  +}
  +
  #[derive(Debug, StructOpt)]
  enum Command {
  Cat {
  @@ -47,7 +53,7 @@ enum Command {
  }
  fn main() -> Result<()> {
  - let command = Command::from_args();
  + let command = Opt::from_args().command.unwrap_or(Command::Sleep);
  println!("Executing \"{:?}\"", command);
  match command {
  Command::Cat { path } => cat(&path)?,
  