Function display

backend/src/types.rs:604–610

()

        #[test]
        fn display() {
            let id = RepoId::wiki();
            assert_eq!(
                format!("{id}"),
                "32212616-fc1b-11e8-8eda-b70af6d8d09f".to_owned()
            );
        }

        #[test]
        fn validation() {