fn returns_nil_if_no_retvalue_in_rust(ruby: &mut Ruby) {
    let mut player = Player::default();

    ruby.plug("player", &mut player);

    assert_eq!(Value::nil(), ruby.eval("PLAYER.move_left").unwrap());
}
/// If no return value is specified in Rust, the marshall function should automatically
/// return the Ruby value `nil`.
If no return value is specified in Rust, the marshall function should automatically
return the Ruby value `nil`.
If no return value is specified in Rust the marshall function should automatically return the Ruby value ` nil ` .
fn returns_nil_if_no_retvalue_in_rust(ruby: &mut Ruby) {
    let mut player = Player::default();
    ruby.plug("player", &mut player);
    assert_eq!(Value::nil(), ruby.eval("PLAYER.move_left").unwrap());
}
fn returns_nil_if_no_retvalue_in_rust ( ruby : & mut Ruby ) { let mut player = Player :: default ( ) ; ruby . plug ( " " , & mut player ) ; assert_eq ! ( Value nil ( ) ruby eval ( " " ) unwrap ( ) ) ; }
If no return value is specified in Rust, the marshall function should automatically
return the Ruby value `nil`.
If no return value is specified in Rust the marshall function should automatically return the Ruby value ` nil ` .
ruby
&mut Ruby
ruby
&mut Ruby